Unsubscribe from an auto-renewing subscription

If you've purchased an auto-renewing subscription from within the ShowMyPC app, it will be listed under the Manage App Subscriptions section of your Account Information Screen. You will need to sign in to your iTunes Store account on your computer or iOS device to modify or cancel your subscription.

IMPORTANT: Uninstalling the app will not automatically stop your subscription. You must actively cancel the subscription using the process described here. If you uninstall the app but don't cancel your subscription first, you will still be charged. You can always unsubscribe or change the subscription plan anytime before the current subscription period expires.

Turning off auto-renewing subscriptions on an iOS device

1. On the Home screen, tap Settings.
2. Tap App and iTunes Stores.
3. Tap your Apple ID.
4. Tap View Apple ID. You might need to sign in.
5. Under Subscriptions, tap Manage.
If you don't see a subscription in iTunes and are still being charged, make sure that you're signed in with the correct Apple ID. If so, you might have subscribed directly with the provider and not through iTunes. In this case, please contact the content publisher or app developer directly to cancel your subscription.
6. Tap the subscription that you want to manage.
7. Turn off Automatic Renewal to cancel a subscription. Your subscription will stop at the end of the current billing cycle.

Turning off auto-renewing subscriptions on a computer

1. Launch iTunes on your computer.
2. Choose Store > Sign In from the iTunes menu.
3. Enter your Apple ID and password when prompted.
4. Choose Store > View My Account. (You may be asked to re-enter your Apple ID password. Click View Account.)
5. In the Account Information screen, scroll to the bottom of the page to the Settings section.
6. Click Manage to the right of Subscriptions.
If you don't see a subscription in iTunes and are still being charged, make sure that you're signed in with the correct Apple ID.
7. In the Manage Subscription screen, click on the subscription that you would like to manage.
8. Click the Off radio button to turn off Auto-Renewal.
9. You will see a confirmation window asking you to confirm.
10. Click "Turn Off" to proceed.
(Note: When you turn off Auto-Renewal, you will no longer continue to be billed for your subscription. However, your current subscription will continue until it expires, with no pro-rated refund.)

Reference: https://support.apple.com/kb/ht4098