MCI Residential Service ripoff continued billing after account was cancelld Atlanta Georgia

I paid in full the outstanding balance on my MCI account on 10/22/05 and cancelled the account, switching my business to Comcast.

MCI processed the cancellation on 10/23/05 and sent me an email confirming the cancellation.
I received a bill from MCI for further charges on 11/12/05.

I immediately emailed MCI to address the error.
I received a call from MCI at 8:27 a.m. on 11/13/05 during which the MCI representative acknowledge that MCI had made an error.

I have made multiple requests for confirmation in writing that this was MCI's error and that my account was paid in full on 10/23/05 when the cancellation was processed, but MCI has refused to stand by the affirmation given to me verbally by their representative.
I instructed MCI not to contact me again by telephone, but MCI has continued to harass me with repeated telephone messages.

Michael
Boston, Massachusetts
U.S.A.