MTN - I don't have an account with you!

I was contacted by Shapiro Shaik Defries & Associates (Reference ********** 622) in August 2018. They told me that I owed MTN R16,458 for a cellphone contract that opened in December 2017, although I never ever had any cellphone contract with MTN. My name and identity number was used when this account was opened. I forwarded an affidavit and a copy of my identity document to Shapiro Shaik Defries & Associates on the 8th August 2018 in the hope to resolve this issue as fast as possible. I have telephonically followed up with them 3 times, but the only answer I get is that they forwarded my e-mail to MTN and that they are still busy. My credit rating has always been excellent, but this issue with MTN has caused my my credit rating to fall to a very poor level (level 5). Surely MTN has a responsibilty to ensure that all new customers provide them with the correct information. Surely the person that opened this cellphone contract had to provide MTN with banking details; address; etc. and this ***** could have been prevented.