Does a store have to pay for unauthorized debit card purchases?

Say a debit card is stolen and used at a store. Who has to pay for the charges made on the card?|||Your bank will backcharge the merchant. It is then the merchants problem. Same with a credit card.|||Did you cancel the card when you found out it was stolen? How could someone stole your card and knew your PIN? If you cannot answer these questions, it is your responsibilities.|||You do.