You cant fix stats because there is nothing to fix it from since ads are temporary and removed. You can go into your cp_stats table in phpmyadmin and fix the amount via the database if you want.
Now as far as stats and auctions if I look at the editproduct.php script if you close an auction then the stats are updated
Code:
Content visible to verified customers only.
Likewise if you resell an ad since that indicates that functionality is there for a user when there buyer falls though there is code to minus out the amounts
Code:
Content visible to verified customers only.
So as far as those functions I did a little test
auction - PhotoPost Classifieds
I opened and closed an auction on my test site and the stats increased when I closed it which it should and then I relisted it and they where subtracted fine which they should.
what version are you using by the way?