When some of my students withdraw cash from the ATM. They often forget their bank cards. I was very surprise before but then I knew the reason.
In China when you withdraw money from the ATM, money always comes first then the machine will remind you to take your card. So if you come to China and use an ATM. Be careful! Remember to take your card after you get your cash.
If you forget the card, It either will retain in the machine or steal by others. If the retained by the ATM, you can go to the bank to get your card back. If it stole by others you can also get a new card from the bank and remember change your password.