Incorrect product sold to client and client gets billed for product returned and not used

Late September I called MTN Direct and told the sales person I wanted to enter into a contract for a pocket router. The salesperson sold me without my knowledge. Once the product was delivered, i opened the package. Not only was it a ****le instead of a pocket router but no sim card was included. I contacted MTN Direct and informed them of the incorrect product and missing sim card and said I returned everything to an MTN Store. I sent them various emails asking if the incorrect product was collected.

My email requests were ignored and I have now been billed for two months for a product i dont have and never used. I sent them another email asking for a refund but yet again, no word from them