Credit card fraud + hotel

i work at retail and one of my first time clients offered me a free room at one of the top hotels as an appreciation of my customer service. My bf and i checked in and it was under my name and name of client. We did Not give any of our credir cards and we didnot pay for deposit. All we did was register as guests. Upon check out, client did charge everything to him. One month later, hotel calls us and informs us that that client was a credit card fraudster and nasa jail na. Hotel is now charging us for the room saying we occupied it even if we informed them it was a gift and that i didnt sign Anything that i owe them money. Should we really be paying for the room? Hotel says they will file a case if we dont pay. Pls help.