Oriental Bank Of Commerce — Money Debited without any transaction through atm

Sir I have not done any transection through atm on 17.08.2015 but then also transection was done and when i call customer care they told to talk to home branch but when i call them they told that it was done through atm but when i ask them from which atm and where they told that we dont know and you need to visit bank but now i am in home and i opne account in my university and i havent dont any transection as my transection id is CWDR/00231011/[protected]/[protected] so please help me as my contact no is [protected]