It is understandably frustrating to be told by Apple that the developer must issue a refund, or to see a charge after you thought you had cancelled. The reality of how these subscriptions work is that, because Apple and Google process the payments, the refund decision genuinely sits on their side — we are not able to issue or force a store refund ourselves.
The most effective path is to go back to Apple or Google support with the details, since they review each request against the account and transaction history, and to confirm that the subscription is fully cancelled so nothing renews again. If you were charged after a cancellation you had already confirmed, or you see a duplicate charge, do contact support@vagustim.io and we will help look into the account side with you