Complaint

I have cancelled my contract in November last year and still i get a bill and everytime there is a different story when i call in and speak to an agent. Yesterday 3March 2022 I called in again and was holding and was placed three times to the cancellations department by the agent with no luck of getting through. She told me that she will call me back to escelate it to the cancellations department but again no call back.i am getting a bill every month for this still.I am not sure how to do this anymore as the agent told me that i cannot send an email with this query i have to keep calling the cancellations department.I am now fedup to this point and need urgent assistance.Email me on ***