Why does getline get skipped over? (c++)

Question

I want to create an ATM simulation for a school project and the program is working alright until I try to find out what happens when I input all the wrong things (for if-else statements).

When it reaches the last one, the program somehow skips over the getline code and comes back to it when the if-statements returns false, which will always return false on the first run since I couldn't even type in the answer yet. (program isn't fully completed yet so some switch cases are not considered)

#include <iostream>
#include <iomanip>
#include <string>

using namespace std;

void verified()
{
    cout << "\n-------------------------------------------------------------------";
    cout << "\n\n\t\t\tAccount Verified!";
}

void notverified()
{
    cout << "\n-------------------------------------------------------------------";
    cout << "\n\n\t\t\tInvalid PIN number.";
}

int withdraw(int a, int b)
{
    int withdraw = 0;
    withdraw = a - b;
    return withdraw;
}

int main()
{
    string pin, MainAccount, accNum1, accNum2, accNum3, pin1, pin2, pin3;
    string yesno, yes, no;
    int options;
    float balance, withdrawAmount, depositAmount, finalWD;

    accNum1 = "193763896";
    accNum2 = "193549879";
    accNum3 = "193285015";

    pin1 = "092703";
    pin2 = "122903";
    pin3 = "122003";

    cout << "\t\t\tATM Simulation";
    cout << "\n-------------------------------------------------------------------";
    cout << "\n\t\tWelcome to the ATM Simulation!";
    cout << "\n-------------------------------------------------------------------";

    cout << "\n\nPlease enter your Account Number\t: ";
    getline(cin, MainAccount);

    if (MainAccount == accNum1)
    {
        cout << "\nPlease enter your PIN\t\t\t: ";

        getline(cin, pin);

        if (pin == pin1)
            verified();
        else
        {
            notverified();
            return 0;
        }
    }
    else if (MainAccount == accNum2)
    {
        cout << "\nPlease enter your PIN\t\t\t: ";

        getline(cin, pin);

        if (pin == pin2)
            verified();
        else
        {
            notverified();
            return 0;
        }
    }
    else if (MainAccount == accNum3)
    {
        cout << "\nPlease enter your PIN\t\t\t: ";

        getline(cin, pin);

        if (pin == pin3)
            verified();
        else
        {
            notverified();
            return 0;
        }
    }
    else
    {
        cout << "\n-------------------------------------------------------------------";
        cout << "\n\n\t\t\tAccount not recognised.";
        return 0;
    }

    if (MainAccount == accNum1)
        balance = 5000;
    else if (MainAccount == accNum2)
        balance = 12000;
    else if (MainAccount == accNum3)
        balance = 18000;

TRANSACTION:
    cout << "\n\n------------------------------Options------------------------------";
    cout << "\n\nBalance Inquiry (1)";
    cout << "\nCash Withdrawal (2)";
    cout << "\nDeposit (3)";
    cout << "\nChange Pin (4)";
    cout << "\nAbout us (5)";
    cout << "\nExit (6)";

    cout << "\n\n-------------------------------------------------------------------";

    cout << "\n\nPlease select a transaction: ";
    cin >> options;

    switch (options)
    {
    case 1:
        cout << "\n\n-------------------------------------------------------------------";
        cout << "\n\n\t\t\tBalance Inquiry";
        cout << "\n\nYour account balance is " << fixed << setprecision(2) << balance << " php.";
        break;
    case 2:
        cout << "\n\n-------------------------------------------------------------------";
        cout << "\n\n\t\t\tCash Withdrawal";

    WITHDRAW:
        cout << "\n\nPlease enter the amount you wish to withdraw (Max amount is 5000.00 php per transaction): ";
        cin >> withdrawAmount;

        if (withdrawAmount <= 20000)
        {
            if (MainAccount == accNum1)
                finalWD = withdraw(balance, withdrawAmount);
            else if (MainAccount == accNum2)
                finalWD = withdraw(balance, withdrawAmount);
            else if (MainAccount == accNum3)
                finalWD = withdraw(balance, withdrawAmount);
        }

        else
        {
            cout << "\nWithdrawal amount exceeded. Please enter an amount lower than or equal to 5000.00 php.";
            goto WITHDRAW;
        }
        cout << "\n\n-------------------------------------------------------------------";
        cout << "\n\nWithdrawal successful. Your new balance is " << fixed << setprecision(2) << finalWD << " php.";
        break;
    case 3:
        cout << "\n\n-------------------------------------------------------------------";
        cout << "\n\n\t\t\tDeposit";

    DEPOSIT:
        cout << "\n\nPlease enter the amount you wish to deposit (Max amount is 20000.00 php per transaction): ";
        cin >> depositAmount;

        if (depositAmount <= 20000)
        {
            if (MainAccount == accNum1)
                balance = balance + depositAmount;
            else if (MainAccount == accNum2)
                balance = balance + depositAmount;
            else if (MainAccount == accNum3)
                balance = balance + depositAmount;
        }
        else
        {
            cout << "\nDeposit amount exceeded. Please enter an amount lower than or equal to 20000.00 php.";
            goto DEPOSIT;
        }
        cout << "\n\n-------------------------------------------------------------------";
        cout << "\n\nDeposit successful. Your new balance is " << fixed << setprecision(2) << balance << " php.";
        break;
    case 4:
        cout << "\n\n-------------------------------------------------------------------";
        cout << "\n\n\t\t\tChange Pin";

        break;
    case 6:
        cout << "\n\n-------------------------------------------------------------------";
        cout << "\n\nThank you for partnering with us. Please come again!";
        return 0;
        break;
    }

YESNO:
    cout << "\n\n-------------------------------------------------------------------";
    cout << "\n\nMake another transcation? (y/n) : ";

    getline(cin, yesno);
    yes = 'y';
    no = 'n';

    if (yesno == yes)
    {
        goto TRANSACTION;
    }
    else if (yesno == no)
    {
        cout << "\n\n-------------------------------------------------------------------";
        cout << "\n\nThank you for partnering with us. Please come again!";
        cout << "\n\n-------------------------------------------------------------------";
    }
    else
    {
        cout << "\n\n-------------------------------------------------------------------";
        cout << "\n\nPlease type a valid option.";
        goto YESNO;
    }

    return 0;
}

So this is what the output looks like:

-------------------------------------------------------------------
                Welcome to the ATM Simulation!
-------------------------------------------------------------------

Please enter your Account Number        : 193763896

Please enter your PIN                   : 092703     

-------------------------------------------------------------------

                        Account Verified!

------------------------------Options------------------------------

Balance Inquiry (1)
Cash Withdrawal (2)
Deposit (3)
Change Pin (4)
About us (5)
Exit (6)

-------------------------------------------------------------------

Please select a transaction: 1


-------------------------------------------------------------------

                        Balance Inquiry

Your account balance is 5000.00 php.

-------------------------------------------------------------------

Make another transcation? (y/n) :


-------------------------------------------------------------------

Please type a valid option.

-------------------------------------------------------------------

Make another transaction? (y/n) : (this is where you can start typing)

I've been trying to solve this for hours but can't find what's going on, can someone explain?