Canceled contract in arrears

I have been harassed to pay an installment for a canceled contract. Firstly it takes months to get a response from the company. Then I get calls from the o renew then I told them that I have decided to cancel my contract. Then I get installments still going off. I reversed it and all of purple I owe them. The ''make arrangements'' number never gets answered! I don't know if there are different departments but they are clearly not seeing the same information and it's very difficult to get a he right people via call. Multiple emails need to be sent to get any form of service but they are very quick to take the money.