Overheating router

I took out home internet sometime last year. It was a bumby ride from the beginning. I am struggling with connection. Last week on the 17th Jan my almost burned down. The router plug caught fire and burned the wardrobe and the clothes. Luckily I was home and I could extinguish fire but it can do more damage. I moved the router to the living room. The past Saturday it was over heating which It did since I had it. I touched it it was extremely hot. I had to switch it off. So now I trying to call customer care I can't get through because I don't have Mtn number. I called MtN Centurion branch, I spoke to Patience. She said I must buy cable and will be charged and if the router is replaced I will be also charged. Clearly the router is faulty...why should I be charged?¿?