Month to month cancell anytime home wifi

Took a home wifi pro infinity plan R1085 month to month Debited R2027.00 (R1085 + so called pro rata). Upon trying to cancell this which mind u is cancell anytime there is now a cancellation fee of R4999.99 even though the terms state to being in the router and sim card.No body knows what this amount is for. The call centre tells you to go to the store, the store says its online and call centre does business differently. Mind u this is supposed to be MTN as a business but blame is being shoved around. Now im stuck because i cant cancell their so called, "cancell anytime" contract because i will be billed R4999.99. False advertising at its flippen best.