Debit cards offer much less protection from liability than credit cards, which means it may be more difficult for you to recover any lost funds. Canceling or disputing charges on your debit card account is most effective when done in a timely fashion. Canceling your account soon after you notice misuse should be a top priority as it will save you from having to dispute multiple charges over a longer period of time. Stay in contact with your bank for updates on your account.
Gather all information about the unauthorized charge to your debit account. Most often the need to cancel a charge is brought about by debit card theft and fraudulent use. Keep a close eye on your debit card balance, and check it once or twice each day to spot any irregularities.
Call the store as soon as you notice the incorrect charge on your account and ask if it is still pending. Sometimes there is a lag between when a purchase is initially made and when the funds transfer to the store. The store may be able to stop the transfer before it is completed. If it is unable to do so, you will have to dispute the charge with your bank.
Call your bank immediately to let them know there is an unauthorized charge to your card. It may take a day or two for the charges to show up in your account, so the bank may not be able to provide immediate help. Make sure that you cancel your current card and order a replacement with a new number.
Contact the police if the amount charged to your debit card is significant. Have them open an investigation into who placed the charges on your card. These investigations are time consuming and may not yield any arrests (or even suspects), so remain patient while waiting for a response.