Non filing and non payment of mvat by selling dealer

I made purchases from a registered dealer and paid MVat (Invoice copies as per the MVat laws) on the purchases so made. Later I claimed the input credit for the same. However the selling dealer failed to file the Mvat returns as well as to pay the tax amount. Now I have received a notice u/s 64 of MVat Act, 2002 in form 603 to pay the full tax as well as interest and penalty on the same which is not acceptable to me. I have the Invoice copies as well as the payment details to the selling dealer. Kindly advice.