Supersonic zero service and trying to ****** money out of me for the router courier after cancellation

Upon cancellation of the month to month subscription and a calendar nptic period of one month, this company is wanting me to pay R250 courier fees for a router that they want returned. I was not told of any courier fees when the product was sold to me, and am therefore not paying a cent. Bunch of ****** trust me do not support this company with such poor service......they keep sending emails I respond but no reply.....utterly useless