MTN & their ***** department

In February 2021, Someone committed ***** by opening a new line on my contract..I reported this immediate to MTN SA and submitted all required documents, and I was told it will be resolved within 21 day by their ***** department..The ********** account that was opened did some transactions which now appeared in my statements as if now I’m owing MTN thousands..MTN has not removed this balance from my account and have failed to resolve this matter even after my numerous follow ups…I used their phone line, Twitter, email and still they have done nothing.. Today (27th Aug 2021) I receive a message from them saying I must pay that ***** amount in 2 days as it will hurt my credit rating! Is this incompetence or negligence or don’t care attitude from MTN? I felt this was a deliberate attack to my credit for absolutely no reason except for their failures. Bad bad bad!