If you believe that the loss of items/currency is due to unauthorized access on the account, you should first secure your account by changing your password.
Before submitting a ticket, please make sure to check all of the places where these things could be (e.g., inventory/bag, bank, other characters).
If you are still unable to locate your item please, please login to the support site with the affected account and submit a ticket under the heading: I need assistance for an issue within a game. For the Issue Type dropdown, select Missing Item. The ticket form will then automatically adjust to request specific details regarding what is missing. Please fill it out as completely and accurately as possible so that we can investigate the incident quickly and efficiently.
IMPORTANT: We cannot guarantee restorations on all lost items/currency. If a restoration is offered, we also cannot guarantee it will be the exact item that was lost; in many situations only the base item can be restored. Ultimately it is the player's responsibility to maintain the security of their account, and take caution when handling their items.