VakıfBank Charged Me Double the Promised Interest on My Overdraft Account

The interest on the overdraft account I used at VakıfBank ended up being almost double what it was supposed to be. I was told the interest rate would be about 5%, so I was really surprised when I saw that nearly 11% was taken out of my account. I really don’t get where this difference came from and think there’s been a big mistake in the calculations. Dealing with such a big charge and not getting a clear reason has really messed with my trust and put me in a tough spot financially. I'm asking for a detailed look at the transaction, a recalculation using the right rate, and a refund for the extra amount that was charged. I hope VakıfBank deals with this matter openly and thoughtfully.