Originally Posted by
edgecrusherO0
They found out your e-mail somehow. Either when they accessed another games database (Cryptic, Blizzard, Trion and most other MMO devs have had their databases accessed at some point) or they "brute forced" your email since the GW2 site apparently lets you know if the email you entered is attached to an account or not.
As long as you have a secure password, I wouldn't be too concerned since they apparently seem to be accessing accounts through brute forcing it. Hopefully ArenaNet can continue to implement more security measures on their side.