Strange message
You (iCloud) has sent a message that mij payment options for mij iCloud account would be incomplete. HOWEVER the instructions don't lead to a solution.
Dear irJW Wijers,On 07-03-2021 you are scheduled to be charged € 2,99 for your 200 GB iCloud storage plan, but there is a problem with your payment information.Please update your payment information as soon as possible. If we cannot successfully charge your account, it will be downgraded to the free 5 GB plan and your service may be affected.
Follow the instructions below to update your billing information:
1. Go to Settings > [your name] > iTunes & App Store.
2. Tap your Apple ID, then tap View Apple ID. You might be asked to sign in.
3. Tap Manage Payments (if you’re using an older version of iOS, tap Payment Information) and follow the prompts.
You can also update your billing information on a Mac or PC.The iCloud Team
MacBook, macOS 11.2