Angry customer

I had a contract with mtn that was suppose to be 36months, due to lack of knowledge I didn't cancel the contract and have been paying for over 4yrs now irrespective that I called them to report a ****** phone and both sim cards that were contracted a year into the contract, I stopped the debit order and it didn't go through and the lady called me to say my acc is in arrears I tried to explain my situation and she advised me to cancel the contract of which I did and was told it can't be canceled before I pay cancelation and arrears, I paid all that after the call, to my surprise few wks ago I got a call saying my acc has been handed over to the lawyers and I must pay if I still want their services, I gave the lady the cancelation refno and hung up. I'm tired, the emails are not responded to and mtn is messing my life big time, my credit score took a downfall since...