There is an Apple article that explains how to cancel subscriptions. Click on the following link: If you want to cancel a subscription from Apple - Apple Support
or use an internet browser to cancel as described in How to cancel Apple TV+ - Apple Support
or cancel in the Apple TV app as described in Manage subscriptions in the Apple TV app - Apple Support
Also not that an Apple TV+ subscription in the U.S. is $9.99 per month. You may have some other charge on your account. This is primarily a user-to-user support forum; other Apple users like you. We don't have access to information about charges to your account. Apple has a support article about charges — see each of the steps in the following instructions. They include information on contacting Apple Support if the other steps don't help. See: If you see 'apple.com/bill' on your billing statement - Apple Support
Also, after cancelling (so that it won't be charged again in the future), see the following to try to get a refund: Request a refund for apps or content that you bought from Apple - Apple Support