Home cable STB (make indigital)
Not working

Dear Sir,

I had purchased a home cable STB from my local cable operator in Feb. Now during last month (Nov) the set up box stops working. i talked to the home cable poerson they said that the STB need to be changed and that is for free of cost from the local cable operator. but they are not listening. and from the last month i was unable to view any channel. so it is very iiritating now. what should i do??