Ebay do send you an email to your Ebay inbox.
You can also see who has cancelled the bid.
Find the listed item and click on it. Beneath the price, if it now says '0 bids' click on that.
You will see the bidder's name and the reason for the bid retraction.
I always add people who do this to my 'blocked' list.
"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)