I had the same problem about two weeks ago; but my problems didn't seem to start until I deleted the first one. In my frustration, I sent a message to the chessadmin telling them about this problem and asking that they stop sending me these trophies.
To date, I haven't received any more anniversary trophies; but, I don't want to speak too soon.
~The Doctor
I've gotten a "Happy Anniversary" trophy from the site every day for about a week now.