DRI*ARENA Charge
The best way is to contact customer support and explain the situation in as much detail as you can.
Digital River (Ireland, I think it is) (for ArenaNet) is the service provider for in-game cash purchases. If you did not purchase something, you should contact the Billing CS Team via the ‘Support’ link above/below and ‘Submit a Ticket’ for assistance.
Good luck.
If you havent bought any gems etc then im not sure how the discussion forums can help you.
Submit a support ticket and they will be able to tell you exactly what has happened.
Thank you for the help i will do so.