If you are having trouble changing your TV Provider, it's likely that you have SSO (Single Sign-On) enabled through the Settings on your device. For your iOS device, we have some steps to help fix this.
1. Select 'Settings' on your device and scroll down to TV Provider
2. Once you choose TV Provider, on the next screen select 'Sign Out'
3. Select your new TV Provider and enter your Username and Password.
If you continue to have trouble, though, please select 'Submit a Request' at the top of this page and email us for assistance.