I doubt your first issue is related to your DNS problem unless DirectAdmin totally botched that accounts creationg.
Disk usage is gotten directly from the system quota now and bandwidth usage is calculated from logs, both during the tally. Has more than 24 hours passed since the accounts were created?(To allow the tally to run).
Does running the tally manually update the statistics... for any accounts?
Also, what Operating system and version of DirectAdmina are you running?