What you did was perfectly fine. If there is any most basic demand on a postal or email correspondence chess player, it is to write down his moves properly and carefully when sending them, because these are the moves that count.
That is just like touch move in OTB, and just like avoiding mouse slips in internet chess. There, what you put on the board is what counts, and one never gets to take back a move in a competitive game.
I was playing a correspondence game against an opponent and was up a rook and a bishop. The problem was, he had mate in 1.
I'm playing black.
He emails 22. Qh7# game over
Qh7 is not mate! So I respond that the game is not over and replay with Kf8.
He emails back
Oh I meant Qh8# sorry
Apparently he realized that that wasn't mate either, and in a separate email:
Oh I meant Qh6# sorry
The USCF correspondence rules state:
Missing or mistaken announcement of
check, capture, or "e.p." does not invalidate a move. Diagrams
or commentary have no significance in disputes over move
legality.
So I emailed the TD and the opponent to get a ruling on the game in question. Once I did this, my opponent resigned as my king was now out of danger and he was down a rook and a bishop.
Was this a cheap shot by me? It certainly doesn't feel very sportsmanlike, but I don't feel like I should let someone take a move back in a rated game.
Opinions appreciated.