Tatasky settop box

Hi, I have been using TataSky HD+ for over a year. Recently I moved to my own 1st floor apartment where TataSky line of sight is not clear hence I can't use it. When I tried to use tatasky settop box with cable connection it didn't work. I asked tata sky and they said THEIR set top box won't work with anything but tata sky DTH. I paid rs 4000 for this box and I wasn't made aware of this condition. Tata Sky has refused to take it back and refund my money also. Please advice.