Cannot use WiFi router and received excessive bill

I have a data contract with MTN. I upgrade in November 2014 from a 1 Gig contract to a 10gig contract inclusive of a WiFi router with dual sim cards on my IPad and one for the WiFi. Needless to say the WiFi did not work as the sim was not RICA. This was done and 24 hours later it worked. Then I get a bill for R2351 whereas my 10GiG bundle cost me R479 per month. This was querries on 18 Dec 14. 23 Jan 15 MTN Customer care responded - sorry for the delay we will look into the matter. Till date no response. In the meantime my WiFi router stppped working. I cannot use it at all. <br> I went to the Kolonnade outlet and the Shop Manager lodge the same complaint with Customer care. With the documents in my procession and as explained to me by the manager, the sim in the WiFi router is limited to 300MB and not the 10 Gig as per my contract. Regardless of this and all the calls made my WiFi router still does not work and the Customer Care centre still has not answered me and or the store manager<br> <br> I need and answer, I need my money back and most of all I will cancel this contract. The service and after sales service is poor, NO none existing