ATM password

everytime we need to type the password before doin' any operation. but do you know when the password is checked?

before operation? no. i found it this mornin'. i should type the wrong password but still allowed me to choose the operation. after choosing, the screen suddenly showed the password was wrong. instantaenously, i thought the machine was hacked and i withdrew the card immediately.

back to home, i phoned the credit card customer service (i made i can access my saving account by the card) and the service said the password is not checked at first! o...

P.S. i found i cannot change my card password on atm but i forgot to ask the customer service.