MTN ****med me

I have a month to month router with MTN and was informed that it is unlike a contract and I’m not obliged to pay and get Wi-Fi every month. So for the past two months I didn’t load wifi. I’ve now received an SMS from MTN letting me know I’m being charged and amount of R2802 called a claw back fee. Therefore I was given misleading and incomplete information on the day of purchase. Now I’m expected to pay this fee for Wi-Fi I didn’t load. This is unacceptable