My apologies if this has been asked before, but I can't see it in recent topics, at any rate.

Two questions regarding how the messaging system works:

1. When you send a seller a message, it will say on their page that said vendor "Has an unread message from you" - when that notice goes away, it is safe to say that the seller has since opened the message, aye?

2. If a seller deletes messages you sent to them at one point, will they vanish from your Sent side too? A while ago (in a period of about 20-30 days since the first message in correspondence) all the messages I had sent to a vendor inexplicably vanished. However, I noticed they vanished the day after said vendor had returned from holidays and put up a post saying they were working through all their messages. So, I wondered had they deleted the messages I sent them and thus that causes them to get deleted from my side too. (I actually asked the vendor about my missing messages to them and they avoided the question.)

Thanks in advance!