I'm sure I'm stating the obvious here.. but you're going to have to expect that. A lot!
I hope that members complaining about that isn't the worse you've had to deal with so far. Cause if you want to delete your user database for that, then I must say.. Prepare for much worse.
Actually, the more I think about it.. one of my sites has been up for a good three and a half years now and I have had only a few people post complaints. And they were valid, understandable complaints. I guess I lucked out with that one.