Terrible service

I am extremely disappointed at this brand, today I got a call from debt collectors saying that I owe MTN R6000 for a contract I never took, I was told to visit a nearest store, I went to the Sandton store I and was shocked at the discovery. when I got to the store I was told that took out a contract in April 2021 for 2 cellphones (which I have NO knowledge of). I requested to see the contract which I "supposedly" signed and I was told that they cannot show me the contract as my account has been frozen, I requested to see a contract statement that was supposedly being sent to me monthly, I was also told that this is not allowed for the same reason, even after I provided the gentlemen with my ID. I found this to be very shocking, when I got home my mother got an SMS saying the same thing that she owes MTN close to R6000 yet we have never used MTN phones before.