Problem with a purchase shown on your statement: Credit card

There were 6 purchases made with my Citibank debit card that I did not make. They happened in a state/city that I've never been to and I know no one in. Citibank told me that : Based on the information that you provided and the results of out research, we are unable to honor your request for reimbursement. Our decision is based on the following : - You informed us that your Citibank debit card has not left your possession. - Both your Citibank debit card and PIN were required to perform the transactions. I have already appealed this decision once with Citibank.