Canceling subscription

These support pages provide comprehensive information about how to manage your subscriptions - both from your devices, or from your AppleID account:

Subscriptions and Billing - Official Apple Support

How to cancel a subscription from Apple – Apple Support

If the subscription that you want to cancel is not listed – Apple Support

Start reading this support page:--> Subscriptions and Billing – Official Apple Support, and check each of the first 4 sections.

If you cannot find the information you were looking for, please contact iTunes Store Support Team directly, using this link:--> iTunes Store & App Store – Get support for various issues, and choosing: your country, then Apple ID, then iTunes & App Store. If your problem is not among the options shown there, tap/click on the option “the topic is not listed” and describe your issue.

Regards

Giulio

P.S. IDMS stands for Integrated Database Management System and is what Apple uses for login authentication for all their services.