Money **********ly taken and not return in full

Thrifty erroneously took R635.17 from my account. You admitted the mistake but took 2.5 weeks to return the money. However, the money was taken from an international bank account and has not been returned at the same exchange rate as it was taken. I have therefore lost potential interest on my money and lost money in real terms. Thrifty needs to pay me back my money at the exchange rate it was taken from my account AND return it with interest. It is ***** to take my money and hold it for 2.5 weeks.