When it comes to purchases made without your knowledge, we have no problem reversing a transaction as long as the in-game currency/items haven't been used. However, we sell digital goods and once those goods are consumed there is nothing to refund.
Please see our Terms of Service here:
Particularly the "Digital Items, Prizes" section which states that "Any Digital Items purchase is final and non-refundable."
Aside from that, if you are an authorized user or you’ve put your credit card information in the account, you take full responsibility for any purchases made on the account.
Lastly, you will want to set some sort of password in order to make purchases on your account in the future. This article will help with that: