i was charged twice

We can't, we are fellow users and don't have that ability. If it shows three times on your iTunes account's purchase history, and if you didn't buy whatever it is three times, contact iTunes Support : http://reportaproblem.apple.com or http://www.apple.com/support/itunes/ww (click on your country's flag, the country where you live, and which is therefore the country on the account ; click on Contact Support towards the top right ; click on Get Help under 'Talk To Us’)