Meke sure you have coverage!!

Good day In Jul we got a wifi router for our house and during the sale i confirmed with the sales rep 2 times to make sure we had coverage. At first it did not work and took weeks for someone to help me reca the sim card. It worked for 2 days and then got shut off. We struggled for weeks just to find out that we did not have coverage. I took it back to them in store and asked to cancel everything as they sold me something i could not even use. I was informed that i could cancel my contract at a R6000 cancelation fee. I told them to just leave it as i did not have the money but was told it is already in the system. I refuse to pay the cancelation fee as i was sold something i can't even use!! Now all my contacts phone, tablet and travel router that i have with them is blocked because I can't pay the cancelation fee.