Question 

How to enable and disable the 14-day trial period in BCR for iOS and FineReader PDF for iOS applications?

Answer

If one has never subscribed to a yearly Premium account before, there will be an option to access a free 14-day trial period. Canceling the trial period will immediately disable the subscription. Payment for subscription renewals will be charged to the account within 24 hours period to the end of the current period.

Subscription renewals can be disabled in the iTunes account settings on the device: How to cancel the subscription to Premium Account in an iOS application? 

During the trial period, the funds might be reserved (not proceeded as a payment), which means that the subscription can be canceled. If the subscription is canceled, the funds are returned from the reservation (the period in which the funds will be returned depends on the bank). If the subscription is not canceled correctly during the trial period, funds from the reservation will be transferred as payment.

Please note, that ABBYY does not have access to the purchase history or payment history.

All applications, including ABBYY applications purchased in the App Store, are associated with the Apple ID. ABBYY does not have access to the purchase history. It is connected with the Apple ID and is strictly confidential. The only company that can refund the purchase made in the App Store is Apple. It is possible to report a problem to Apple (as described in the following article https://support.apple.com/en-us/HT204084) and choose "I didn't authorize this purchase".