Cell C *******

Cell C a bunch of *******, I've had a contract with cell c for over four years. I'm on my third device with them but all of sudden since from January their overcharging me claiming that I've been using internet with the sim card which I haven't used since last year!!

I only renewed my contract because I wanted a device, which I've been using with a different sim card. Even at this moment the sim card is still not in use, but cell c already says I've used up R280 for internet!! The nerve and the audicity to deduct an amount that I'm not liable!!