Forced to pay service that i dont have

MTN is a bully and w ****. I app**** for lte wifi and they sent me something that doesn't work in my area according to their consultants. I have returned the device and requested for cancelation on the 4th of December within their cooling period. Only for them to charge me for something in their position already. How??? And they know that they will list me if I don't pay that amount. This is Bullying MTN. You cant be forcing people to pay for service that they don't have. And when you call they keep transfering you to one another. Its like they were trained to do that cz you can go through more than 10 consultants just confirming details and no further assistance