capital one falsely accused of having a capital one credit card and using it to make a purchase in a state which I have never been in Nationwide

I received an invoice from capital one for charges made in a store in one of the states which I have never travelled to.when I called the company to inquire as to how they were able to get my personal information,I was told to file a complaint ,they sent me forms which I had to fill out and send back.After doing all this I was informed by mail that they had found me at fault,even though I have never applied for this card,nor ever will.It has been three years and they are hounding me to pay.I have told them I am not paying someone elses bill and to stop tormenting me.The persist in calling and sending me notices.Is there anything I can do to stop this