1. Go to the school canteen: you can go to the front desk or the administrator of the school canteen to explain the situation and ask for help. They may ask you to fill out an application form and provide some personal information to verify your identity and reissue a new meal card.
2. Find the relevant departments of the school: If the school canteen can't solve the problem, you can consult the school academic affairs office or the student affairs office and other relevant departments, and they may give further guidance or help.
3. Ask your classmates or friends for help: You can ask your classmates or friends around you for help, ask them if they know or have experienced similar situations, and seek feasible solutions from them.
The above are some common solutions I can provide, hoping to help you. If the above methods still can't solve the problem, I suggest you further contact the relevant departments of the school or discuss with your parents for help.