I posted a similar issue yesterday, all of my contents from Joker Box purchases are gone, with their respective mail. There isn't a expiry date on Joker-box items in your mail so it shouldn't disappear, let alone not appear at all after a purchase. So you're not alone in this matter.
It's obviously server-related, so I dont think that there is much YOU can do about it. You haven't played in a while, so you might not remember deleting the character?
It might have been that you hadn't played APB in a while and Tiggs decided to wooosh in and delete a few players data because of storage issues?
I dunno, but Support should be able to help you when they have time.
All mails with items from Jokerboxes are gone, it happened recently. About 8 pages of mails with Weapons and vehicles from Jokerboxes are all gone. Was it removed for a reason or was is a server side error with the Battleye update or another patch?