Worst Company Ever, why can't I terminate service

Been trying to cancel and disconnect service for three months.  Docsigned and have emails where service termination was accepted, yet I still get invoices for service and accounts still active.  Had to drive to local comcast location and dump off equipment because all other methods to return equipment failed.  Have filed complaints with California public utilty commission (they did nothing) and the FCC.  FCC opened ticket and this comcast rep who identifies himself as "Fritz X"  (unbelievable) keeps offering excuses but nothing ever changes.  I keep getting told that service disconnection will happen and that Invoices will be corrected, but it never happens.  Over the weekend I began receiving harrassing emails from collection agencies because Comcast has sent me to collections.  It is a complete nightmare.  I was a business customer for over 10 years and to be treated last this is unacceptable.