How long Decline Trade stays in my mail?

How long Decline Trade stays in my mail? I send trade and hi come back and is in my mail, do i have to accept back my good or can i w8 7 days or more?

And if it disappear after some time what happened with my goods?

I have one for over 10h now, that why i ask.

Plz answer only if you actually know the right answer!

It will stay until BB do a sweep of mailboxes, so if you are thinking of using your mailbox as a temporary store, beware.