Payment in app store
why does it say payment not complete?
iPad (5th gen) Wi-Fi
Do you mean a "Your purchase could not be completed" message?
You may see various forms of a "Your purchase could not be completed" message. Some may show old URLs which will redirect to the current one which leads you to a page to select your country. Since it says to contact iTunes Support, try this:
1. Click on this link --> https://support.apple.com/choose-country-region/media-services
2. Select your country
3. Select: Billing & Subscriptions
4. Select: Subscriptions & Purchases
5. Select: Update payment method
6. Select a chat session or a phone call.