cancelled contract not being cancelled

Hi I've been, just like others struggling to cancel my MTN contracts.... Infact I have proof of cancellation and still my took me to the lawyers saying I had returned debits .. which isn't possible because upon cancellation they gave me a settlement amount for which none of the two contracts was even in its 24 month period... Now I struggle to get their lawyers to leave me alone and has probably made a mess of my credit score... I last reported this and was told to email this proof and I wasn't given a email address... I now need this sorted and want to know how future customers can trust MTN if so many of us have the same issues... It also boggles me that they can tell me I'm owing and everytime I ask how if I have proof they can't answer me after I've even sent those who requested the proof , the proof. I suggest if you want to get to the root of something that I'v cancelled a number of years ago is to check where the documentation that I sent was sent from, which MTN branch