email quota filling fast

just upgraded to centos 5.1

i have problems with backscatter.

also my email accounts. the quota fills in less than an hour and its not mail. deleting/recreating the account leaves the quota full. maybe a couple of kilobytes less.

1) how to delete fictitious quota 2) how to stop it from filling up again

saw a forum post about bayes, but the link was dead.

also after the upgrade/restore my joomla sites have an image display issue. as in they are not. this one i can pry work out unless someone has some hints.