***** MTN cell contract I don't have

Hi chomi name is Ellen, i have been trying to get hold of MTN, I have been getting sms that says I owe R2049.97 for a cellphone contract I didn't take, am a Vodacom customer not MTN now my credit core is very bad I even check my clear core is so bad because of MTN , I need answers, who signed for that phone and the ID of that person who signed and the address were they delivered. Am so angry that people are committing ***** and MTN call center allows people using my details and I told them not to deliver the phone and I called them back to tell them I don't know what they talking about, but suddenly I owe them, I have True caller mtn call center called me to confirm my details for a cell phone contract and I refused I told the lady I was speaking with to confirm them because she's telling me about my delivery that's going to northeast west I told her I stay in joburg and I did not take a cell phone contract on line with you please cancel, so that means they know what's going on, if they check the cell phone conversation on their side they will hear what I said, I need MTN to solve this mess.