Mtn is kaak

I had a contract with mtn and my contract ended amd was not aware that I had to cancel it and I was told that contract was ongoing and I was told i owe mtn and I paid everything, my slice is still closed went to mtn several amd sent proof of payment and I still can't get my number opened. Now I'm being told I gave my number to someone else whereas I have been trying to get my number or Sim swap of my number. Everything is linked to that number. What am I suppose to do. Please run away from mtn