Mtn lawyers are bad rotten meat, no help at all

I have placed an order for wifi router on online with mtn then it got delivered and it was working perfectly fine, so after some few months I decided to return the router to Mtn shop since it was a month to month contract with 100gb that I no longer needed since I was paying R284 because we got fiber on our area that is unlimited for R290 the whole month. So right now some Mtn lawyers says I owe then R3600 for wifi router but the router it has been returned to Mtn shop. So at the moment I'm going back and forth to resolve this issue but not getting any help from Mtn consultant nor Sally Lawyers. Mtn it's bad like rotten meat