Hello Rwithem,
Thank you for reaching out to Apple Support Communities.
We were able to find this:
If you pay monthly or annually for your AppleCare plan
Need to change the payment method for your AppleCare plan? Change your Apple ID payment method.
Need to cancel your plan? You can cancel your AppleCare plan in the account settings on your device. If you don't see your plan when you try to cancel it, finish setting up your account. If you finished setting up your account and you still don't see your plan, contact Apple Support.
If you cancel your AppleCare plan, the monthly or annual billing2 can't be renewed. If you're no longer eligible for an AppleCare plan, you can't add it to your device again.
More details can be found here: Cancel or change the payment method for your AppleCare plan
If the issue persists, it may be best to reach out to Apple directly.
You can do so by going to Get Support.
They will take a closer look and check on available options.
Cheers!