It is very troublesome to sell the Great Wall Card. You have to go to his designated credit card center (Beijing is on the other side of Financial Street). This was before, I don't know if it is now.
3. the password in the password letter is used to provide you with the operation on the ATM machine, and the card withdrawal has nothing to do with the password. The customer service password will be set when the card is opened, and will be used when the card is cancelled.
By the way, if you don't want to use this card, you'd better ask the customer if there will be a fee if you can't open it. If not, you can sell all the cards and don't need them.