How can I get init_point or sandbox_init_point after calling payment.create API with mercadopago?

Question

I have implemented the preference API and I am getting the response which I have attached. Now I am confused about how to get refund with this response or is it possible or not. Can you please suggest some API related to the refund policy?

Thanks for the cooperation in advance.

The response which I am getting:

{
  "processing_modes": [],
  "metadata": {},
  "binary_mode": false,
  "payment_methods": {
    "excluded_payment_methods": [
      {
        "id": ""
      }
    ],
    "excluded_payment_types": [
      {
        "id": ""
      }
    ],
    "installments": null,
    "default_payment_method_id": null,
    "default_installments": null
  },
  "collector_id": 472389951,
  "operation_type": "regular_payment",
  "items": [
    {
      "id": "",
      "picture_url": "",
      "title": "Mojito",
      "description": "Cheesy 8",
      "category_id": "Blah Blah",
      "currency_id": "ARS",
      "quantity": 11,
      "unit_price": 456
    }
  ],
  "payer": {
    "name": "",
    "surname": "",
    "email": "pappu@testuser.com",
    "date_created": "",
    "phone": {
      "area_code": "",
      "number": ""
    },
    "identification": {
      "type": "",
      "number": ""
    },
    "address": {
      "street_name": "",
      "street_number": null,
      "zip_code": ""
    }
  },
  "back_urls": {
    "success": "http://eb7b02b9.ngrok.io/notification/ipn",
    "pending": "http://eb7b02b9.ngrok.io/notification/ipn",
    "failure": "http://eb7b02b9.ngrok.io/notification/ipn"
  },
  "auto_return": "",
  "client_id": "3767495422255439",
  "marketplace": "NONE",
  "marketplace_fee": 0,
  "shipments": {
    "receiver_address": {
      "zip_code": "",
      "street_number": null,
      "street_name": "",
      "floor": "",
      "apartment": ""
    }
  },
  "notification_url": "http://fd7842f1.ngrok.io/notification/ipn",
  "external_reference": "",
  "additional_info": "",
  "expires": false,
  "expiration_date_from": null,
  "expiration_date_to": null,
  "date_created": "2019-10-03T03:35:03.228-04:00",
  "id": "472389951-fdfcf414-18b7-44b3-afd5-5d3cd73fbfc2",
  "init_point": "https://www.mercadopago.com.ar/checkout/v1/redirect?pref_id=472389951-fdfcf414-18b7-44b3-afd5-5d3cd73fbfc2",
  "sandbox_init_point": "https://sandbox.mercadopago.com.ar/checkout/v1/redirect?pref_id=472389951-fdfcf414-18b7-44b3-afd5-5d3cd73fbfc2"
}