To cancel your InTouchApp subscription, you need to go to iTunes and cancel it yourself. We do not have any control over this process and hence the subscription cannot be canceled by us.

On your iPhone, iPad, or iPod touch:
  • Go to Settings > iTunes & App Store.
  • Tap your Apple ID at the top of the screen.
  • Tap View Apple ID. You might need to sign in or use Touch ID.
  • Tap Subscriptions.
  • Tap the subscription that you want to manage.
  • Use the options to manage your subscription.

For more details, please check these links:
https://support.apple.com/en-in/HT202039
https://support.bookmate.com/hc/en-us/articles/202136343-Cancel-a-recurring-subscription-on-iOS