I wish website allow To monitor payment of subscription
Payments are done with the respective play/app store. You can view your subscriptions through your play store settings. You may need to reference your store documentation on how to reference them.
You can also go on to your apple account (if you’re on an apple device ofc) and check your payments/subscriptions to monitor your subscription.
Unfortunately this is not possible due to Apple terms of service. I won’t go into details as it’s been kinda a controversial thing within mobile gaming.