This part of the forum is for questions about Ebay, rather than discussions.
There are lots of posts about this in selling - you could read some of the discussions there or start your own thread.
However, after so many years on Ebay, you should perhaps know that there is no mechanism for a buyer to mark an item as received.
As it says in the email, you will be able to access your payment 2 days after tracking shows delivery, or 14 days after posting if there is no tracking or the tracking is never updated.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)