How to enable a user to buy the same product over and over in android In-app purchases

Question

I am using the Android In-App Billing v3 Library (here is the link). The application I'm making converts Google Play Rewards to cash which is transfer to the desired mobile wallet of the user. I am facing a problem that according to how my app functions a single product should be ready to be purchased over and over again but when I buy the item and try to buy the same item again, it shows me the successful payment activity that is shown when the onProductPurchased() is called.

I know that I have to add consumable products to the play Console but I couldn't find the right way and neither the way how to consume that. This is my first time handling in-app purchases; please guide me through the process. Here are the code and some screenshots of my application.

package com.payapp.app;

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;

import com.anjlab.android.iab.v3.BillingProcessor;
import com.anjlab.android.iab.v3.TransactionDetails;

import java.util.ArrayList;
import java.util.List;

 public class Paytm extends AppCompatActivity implements 
 BillingProcessor.IBillingHandler {


BillingProcessor bp;
Button cont;
String selectedPrice;
Spinner price;

List<String> price_array = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_paytm);

    getSupportActionBar().setTitle("Paytm");
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setHomeButtonEnabled(true);
    cont = findViewById(R.id.continuebtn);


    price_array.add("50");
    price_array.add("100");
    price_array.add("150");
    price_array.add("200");
    price_array.add("500");
    price_array.add("1000");


    /* Spinner Initialization starts */
    price = findViewById(R.id.price);
    price.setSelection(0);
    price.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            selectedPrice = parent.getItemAtPosition(position).toString();
        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {
            selectedPrice = "Football";
        }
    });
    ArrayAdapter<String> categoriesAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, price_array);
    categoriesAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    price.setAdapter(categoriesAdapter);

    bp = new BillingProcessor(this, "<Removed the license key>", this);
    bp.initialize();



    cont.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {


            if (selectedPrice.equals("50"))
            {

            bp.purchase(Paytm.this,"pay_50");}

            if (selectedPrice.equals("100"))
            {

                bp.purchase(Paytm.this,"pay_100");}

            if (selectedPrice.equals("150"))
            {

                bp.purchase(Paytm.this,"pay_150");}

            if (selectedPrice.equals("200"))
            {

                bp.purchase(Paytm.this,"pay_200");}

            if (selectedPrice.equals("500"))
            {

                bp.purchase(Paytm.this,"pay_500");}

            if (selectedPrice.equals("1000"))
            {

                bp.purchase(Paytm.this,"pay_1000");}

        }
    });

}

@Override
public void onProductPurchased(@NonNull String productId, @Nullable TransactionDetails details) {

    startActivity(new Intent(Paytm.this,PaymentSuccess.class));

}

@Override
public void onPurchaseHistoryRestored() {

}

@Override
public void onBillingError(int errorCode, @Nullable Throwable error) {

    startActivity(new Intent(Paytm.this,PaymentFailed.class));


}

@Override
public void onBillingInitialized() {

}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (!bp.handleActivityResult(requestCode, resultCode, data)) {
        super.onActivityResult(requestCode, resultCode, data);
    }
}

@Override
public void onDestroy() {
    if (bp != null) {
        bp.release();
    }
    super.onDestroy();
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    onBackPressed();
    return true;
}

}

Here are the screenshots for better understanding

Mobile wallet selection screen

Product selection screen

The products in my console (managed, no idea how to add consumable products)

Answer 1

Any added product can be used as consumable product. However to achieve this you need to consume the purchased product.

If you read the documentation in the Android In-App Billing v3 Library you'll find your answer.