I am trying to 'break' the loop, but the function just keep looping

Question

I separated my program mainly into two parts. -One is the function which I used 'if' in a 'while' loop,

• one is the main body which is still a 'while' loop but the inside is a switch statement

When I first input d, the main body activates the function and asks for a number. My goal is when the user input a positive value the function will exit and continue to read the code below. However, the 'break' could never be read and formed a loop to ask the amount of money again and again.

I tried to make the function on a separate page that is not within the 'switch' statement, it works! But just doesn't when I insert it in the 'switch' statement.

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>

int GetTransactionAmount()
{
    double transactionAmount;
    
    while(1)
    {
        printf("What is the amount of money you would like to deposit/withdraw?\n $");
        scanf("%lf",&transactionAmount);
        
        if (transactionAmount <=0) 
        {
            printf("ERROR! Please input a valid number above 0\n");
            continue;
        } 
        else
        {
            break;
        }
        
        
    }
    
    return transactionAmount;
}

int main()
{
    char action;
    double totalDeposits, totalWithdrawal, transactionAmount;
    printf("If you would like to deposit, please input D \n");
    printf("If you would like to withdraw, please input W \n");
    scanf("%c", &action);
    
    
    while(1) {
        
    
    if(action == 'D'||action == 'd'||action == 'W'|| action =='w')
    {
        switch(action)
        {
            case 'D':
            case 'd':
                GetTransactionAmount();
                break;
            
            case 'W':
            case 'w':
                GetTransactionAmount();
                break;
    }
    
        //printf("c");
    }
    else
    {
        printf("invalid input");
        break;
    }
   //printf("d");
    }
    

    //getch();
    return 0;
}

I tried to make the function on a separate page that is not within the 'switch' statement, it works! But just doesn't when I insert it in the 'switch' statement.