Corporation Bank — amount wrongly debited from account

Address:

560010

In atm (Atm wdr[protected] at+education dept bang : stan no : 943978) i tried to withdraw rs. 10, 000/- but it was denied, so i later tried t withdraw rs.6000/-, 8000/- and 6, 000/- continuosly and was successfully withdrawn the amount, but in my account statement it is showing rs. 30, 000/- was withdrawn instead of rs.20, 000/-. So kindly check and resolve the issue as the earliest.