Difficulties when canceling contract

I have called MTN 5 times trying to cancel my contract that has expired , the lady who assisted me tried to convince me to take another contract when I refuse she dropped the call, the next one told I’m in the wrong department then transferred to business where I was helped and promised to receive forms to finalize the cancellation I haven’t even received any not even a reference number , all the other times I will speak a consultant the but no one helped