Hi Oscar,
From where did you purchase the Realms subscription? Ideally, the link to cancel is https://account.microsoft.com/services
- Verify that you're signed in with the correct Microsoft account. If you have multiple Microsoft accounts, check each one. Check the confirmation email if you have - it should have the email listed.
- If the Realm appears under your Microsoft account but you cannot manage it, try accessing it from the device where it still works (such as your Phone or switch) while you continue troubleshooting.
If nothing works, Microsoft support should be able to track the payment made previously. Let me know afterwards.
I look forward to hearing from you to get the results of the troubleshooting.