Hi priscilla
If they bounced the cheque, then you were not overdrawn and you should not have been charged interest.
Even if they are charging you interest
€100,000
@10%
= €10,000 per year
= €27 per day.
I suspect that what is happening here is that you are lodging third party cheques to the account and then drawing money out. You are overdrawn on cleared funds, but this does not appear on your statement.
But in any event, you will have to ask them to show you how the interest is calculated.
brendan