Card *****

My post office bank card was ****** while at the ATM and then called the post office to block the card, when i asked the lady to check how much have they withdraw she asked if i have they saw my pin number i said i dont know she then said she will call me back then after few minutes she called and said they withdraw 4000 and my daily limit is 2000 how did the post office approve another withdrawal when my limit is 2000. There was a guy called Maringa who is supposed to be a manager he called me and say they will investigate. My question is how did the get pass my daily limit