Why do I have to give credit card details when I have a cash balance

Hi Madativo,

Welcome to the Apple Support Communities!

From your question, it sounds like you are attempting to make a purchase from the App Store and have available credit on your account, but you are being prompted for payment information when making the purchase.

If the store credit is enough to cover the price of the application and any applicable tax, you should not need a valid form of payment on file. Information on how iTunes purchases are billed is located in the attached article below.

How iTunes Store purchases are billed - Apple Support

If you have enough store credit to cover the cost of purchase and any applicable tax and still receive the notification to add payment information to your account, I would suggest contacting our iTunes Store support so they can look further into this situation and give you accurate information regarding your account.

Apple - Support - Topic Selection

Best regards