1. Query memory: Think back to whether you have bought or applied for this card, such as buying a membership card on an e-commerce platform or applying for a discount card at an activity.
2. Check the information on the envelope: Check whether there is clear sender information on the envelope, such as company name, department name and name. , or whether there is a clear explanation letter.
3. Call the customer service phone: contact the other company or institution through the customer service phone provided on the card to inquire about the purpose and source of the card.
4. Assess personal information leakage: Assess whether you have leaked personal information recently, such as leaking personal information in public places, websites and other places, or suffering from cyber attacks.
Through the above methods, the source of the card can be initially confirmed, and corresponding treatment methods can be taken according to different situations.