Rumor has it that there wasn't gold to be found in any of those messages, but rather 20k - 5x speed trade tokens that flooded the inventory and sabotaged it from being able to open... I had to wait 24 hours for them to fix it. It was a grepo nightmare.
Also, rumor has it that the mail bomb was grepo's nonchalant way of performing a chinese torture on our ears... did you guys hear the sound it made when multiples came in at once? It sounded like a harpy on crack.