unpaid cell bill, with some concerns

I had a cell phone once about 6 years ago but the deal was that i recieved two phones so one was in my sisters name, being young and dumb I never paid mine, my sister following me never paid hers either, they were two seperate bills each month. Now at an address im no longer living at for about 9 years now, i recieve notice that not only do i have to pay the bill i have to pay both, and im being taken to court if i dont. this notcie came from a laywers office with a copy of a court thing in rough draft. thank god I know the ppl that live in the house or i never would have recieved my mail at all, is there anything at all i can do?