Funny. Mine dropped too after I paid for the Directory inclusion AND Sitematch. I ranked high before, but shortly afterward my rankings plummeted to page 6. Don't ask me why, this seems like too many coincidences.
What's interesting is that my rankings crept up back to page 1 where they were. So I checked my stats for Sitematch just for grins and LO and BEHOLD, I had been SUSPENDED for a week or so because I needed to verify an email address or something (I can't remember).
Needless to say that I left it the way it was...not verifying anything and leaving my Sitematch unattended...a win for me since I do not have to pay anymore...
If it ain't broke, don't fix it right?