Question is in the title, thanks.
Answer is in the mailbox expiry date tab.
A couple of years ago, I purchased an annual subscription, which promised rewards for all toons on that account. I did not understand that those rewards would be mailed to me (rather than given outright, as is typical) nor that toons in Arete have no means to retrieve mail.
I assume that Funcom mailed them to me, but that’s just a guess.
But a couple of years later, when I logged that toon and left Arete, the items were not in mail. I assumed the timer expired, but since the toon was in Arete, and could not retrieve it, I have no idea what that expiration is.
Oh, and Funcom limits you on how many times it will mail them to you, apparently based on the assumption that you won’t request them to mail it to you when you are in Arete, despite lack of any information to the contrary,
You can claim your subscription rewards in the item store, and then they will be mailed to you.
Sub rewards have to be firstly claimed through the item store, and are then mailed to you.
The expiry date will still be displayed in the mail window. See the “CLAIM” tab in the ingame store window. Yellow coloured ones are yours for free.
If you claimed the items through the store and never opened the mail and it is no longer there, you would have to contact support directly.