1. I send mail with items to someone
2. That someone receives them, but doesn't take the attachments and instead keeps the messages in his/her inbox
3. 30 days pass and the mail expires, and so it returns to me
4. I, however, don't take the attachments either and let it sit in my inbox for 30 days
What will happen? Will the items be lost forever? Will they be forcibly put in my inventory? Will they keep circulating between me and that someone forever, until either one takes the attachments?