You can pay with your mobile operator account by adding it as a payment method in your mobile app. Follow the instructions below to add your mobile operator to your payment methods:

- If your phone has an Android operating system and you use the Google Play application:

1. Open the Google Play app and click on your profile picture.

2. Open Payments and Subscriptions

3. Tap Add payment method.

3. Select the payment method you want to add.

5. Follow the instructions that appear on the screen.

More information can be found here

  - If your phone is Apple with iOS operating system:

1. Open the Settings app.

2. Tap your name.

3. Tap Media & Purchases, then tap View Account. You may be asked to sign in with your Apple ID.

4. Tap Manage Payments.

5. Tap Add Payment Method.

6. Select your mobile operator as the preferred payment method.

More information can be found here