billing support

I cancelled my service on May 24 via a phone call to customer service.  It showed cancelled in the billing on 5-24 and then somehow was reactivated on 5-26 after I sent all the equipment back.  So I called and cancelled again.  I received another bill, and called again and was told to ignore it as it wasn't showing the credit of the equipment yet.  So now here we are again and same bill.  I had been with Xfinity many years and this has never happened.  Only when I try to breakup with you and you just won't leave me alone.  So I am asking one final time to fix the bill.