Mtn R270 router is a ****

I bought the mtn router on the 26 November 2024 and paid R313 for a R270 they added pro rata fees okay, the delivered it on the 28 November and has never worked i kept calling them until i went to their store at calton centre when i wanted to return it and i was told to go to their main office at randburg this was on the 10th of November when i got home it automatically started working now i am sent the billing email and they are telling me to pay R564 which i dont understand how am I paying so much for a router which costs R270 i have been writing them emails and they are telling me they dont have the payment of R313 i made dont buy the month to month router they claim its not a contract which is a lie