Citibank Credit Card Complaint

Citibank Credit card department,

Closing/Cancelling account California

best buy / citi bank keep charging me small amounts after fully closing and paying off the card and cancelling the debt protection service. Account is closed, but yet still getting bills in the mail, and they are reporting us to the credit bureaus as late / missed payments. I have called multiple times and got the run around, telling me i need to call this other number to cancel something else, but its cancelled! them im told the account is closed and paid in full and should not get anymore bills and then surprise. this is hurting our credit and they cant get their stuff together over there!