Thanks for reaching out. That sounds frustrating. First, can you confirm if the Realms subscription still shows as active under your Microsoft account when you sign in at the Services and Subscriptions section?
If it does, select Manage and check if the cancellation went through. To request a refund, contact Microsoft Billing Support by signing in to your Microsoft account, selecting Help or Contact Support, and choosing the billing category. You can then request a callback or chat with an agent to review the charges and process your refund.