Hello, thank you for contacting apple support communities. I would urge you to check again to make sure your account is fully removed and you are no longer signed in. To do this please go to settings > tap on your name in the top of the screen > name, phone numbers and email and check there and you should be able to change your AppleID from there. If you have already done this and you are still getting the notifications please try restarting your phone by holding the home button anad the power button at the same time until the apple logo appears. If you have done all of these things and you still cannot get rid of the notifications I would recommend that you contact apple support at the following link Official Apple Support. I hope that this helps you. Have a great rest of your day. 🙂