This always sucks, it has happened to the LoB bank a few times, and once since I've been GM. Make sure you tell the GMs in the ticket that you suspect the guildies account to have been hacked. they'll investigate / lock the accounts for that person. Most recently, Alemi's accounts were hacked and raided our bank, the GMs had everything back to us in about a day and let me know they secured Alemi's accounts.