Under what general context? Changing country? Can't update a credit card?
This document explains how to 'Change, add, [review,] or remove Apple ID payment methods' on a Mac or Apple mobile devices; click here --> https://support.apple.com/HT201266
Change your Apple ID payment method if you don't have an Apple device --> https://support.apple.com/HT210755 - PC, MS Surface, Android, Chromebook, online at tv.apple.com
'If you can't remove your last payment method or use no payment method with your Apple ID' click here --> https://support.apple.com/HT203905
- If you are updating an old card and have ongoing subscriptions you may need to first add the new card and make it the primary payment method before deleting the old card.
This article describes how to change your country setting and the requirements and results of doing this:
Read how to "Change your Apple ID country or region" click here --> https://support.apple.com/HT201389
Subscriptions will continue until the expiration date. Canceling them just tells them not to renew after that date. To have it end before that date you need to contact Apple and explain you need it to end immediately.
If you still have problems, click here --> https://support.apple.com/choose-country-region/media-services Select your country, then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.
or:
Contact Apple for support and service --> "See a list of Apple phone numbers around the world." - https://support.apple.com/HT201232