If you purchased a subscription to BrainHQ through the Apple App Store, via the BrainHQ app, then your subscription is through Apple and not directly from Posit Science.
You can manage your subscription by following these steps on your device. The steps are the same for iPhone, iPad, and the iPod Touch:
- Go to Settings > [your name] > iTunes & App Store.
- Tap your Apple ID at the top of the screen, then tap View Apple ID. You might need to sign in with your Apple ID.
- Scroll to Subscriptions, then tap it.
- Tap on "BrainHQ" from the list of Apps with subscriptions
- Select the changes you wish to make to your subscription. You will get a notification of the new date changes. You can turn off auto-renew if you don't want to be charged in the future.
If you have trouble with these steps, you can look to the Apple support website: http://support.apple.com/kb/ht4098
If you need to make a customer service request of Apple you can do so here: http://www.apple.com/support/mac/app-store/contact/
You can find Apple's terms and conditions on refunds at: http://www.apple.com/legal/internet-services/itunes/us/terms.html