MTN NOT DOING THE RIGHT THING

In April 2019 I noticed my account was being debited by mtn,I contacted them to find out a contract had been taken out in my name which I had no idea about.The consultant asked me to send my id copy along with a cancellation letter stating that the account is ********** which I did and said it would be investigated .I then started receiving calls from recovery places telling me I owe mtn and the account has been handed over and have had to explain the story over and over to many consultants and having to forward them the same documents requested by the mtn consultant. I still receive calls and sms’s from recovery places telling me to pay to avoid legal action which is ridiculous.why has nothing been done about this ?it’s frustrating.