Subscription paid and Realm still expired

Hiya. Firstly, we are pretty new to Realms. We have a big family so I signed up for Realms and got one month free. Beauty! Not really knowing the system, I created a Realm and then clicked 'Play on Realms'. It went through the disclaimer and confirmed billing. When I logged off the game, I found it had created (and charged) for a second realm. Okay, no biggie. The first Realm was free. I went to Microsoft and stopped the next billing period for the unwanted Realm. Go forward a month and our bank has been charged for Realms. Microsoft subscription says it's good until December. Minecraft says the Realm has expired (there is only one Realm because I deleted the unwanted Realm) and wants me to pay for another subscription to keep playing. How do we resolve this? Thanks for your time.