All prices at Jackpot Wins are displayed in US Dollars - if you notice on your receipts and bank statements that you've been charged more than what was displayed in the game, it is most likely a result of the exchange rate between USD and your local currency.
If this is not the case, please contact our Support team with as much information as possible - including screenshots of the receipts for the transactions in question, and they will happy to attend to it for you.