Apple ID reset
I have reset my Apple ID but itunes does not recognise. When trying to download new apps the old non valid email address keeps popping up. Cannot delete thisemail address
Did you create a new Apple ID or do a name change on your old Apple ID? It sounds like you created a new Apple ID. If so, all purchases made using the old Apple ID are tied to that ID. You can either delete the purchases and download them again or make a name change using your old Apple ID. If you made a name change, see the second link.
Apple ID email address or password - What to do after you change I suggest doing this before you change your Apple ID or password.