When the bank card has an unknown deduction, you can query the details by querying the details of the bank statement or bank running water. The specific query channel is: 1. Mobile banking logs in to the mobile banking APP of the bank card opening bank, finds the bank card with unknown deduction on the account management page, and clicks to inquire about the transaction details. The mobile banking APP pages of different banks are different, and the specific operation is subject to the actual page display. 2. Online Banking Log in to the online banking of the bank card opening bank, find the account inquiry on my account page, then click the bank card to be inquired, click details, and then inquire about the specific transaction information according to the page prompts. The online banking pages of different banks are different, and the specific operation is subject to the actual page display. 3. On-site inquiry: After you bring your ID card and bank card to the bank to inform the staff, you can inquire about the deduction. You can inquire at the bank counter or at the self-service terminal under the guidance of the staff. In addition to the above three query methods, if the bank card bound by WeChat is recharged on WeChat, you can also query the transaction details of WeChat on the WeChat I-Payment-Wallet-Bill page.