Make sure this is one of the 'Payment methods that you can use with your Apple ID'; click here --> https://support.apple.com/HT202631 For most people this means a card from the same country as the store you are using.
Often the solution is indicated by the exact message you see so if the message varies it is helpful to know that. If you really are seeing one that months later is still telling you to try later then contact Apple and ask them what it means.
Contact Apple. Click here --> https://support.apple.com/choose-country-region 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."
Click here --> https://support.apple.com/HT201232