While working on one clients vps for incorrect disk usage  stats for mails

While the default cpanel has no emails the usage stats showed 750MB.

After going through I found a issue which was causing this

The file causing this issue was maildirsize

maildirsize is the file which shows stats information for each account

root@vps [/home/designse]# find . -iname maildirsize
./mail/designserver.net/gordon/maildirsize
./mail/designserver/gordy/maildirsize
./mail/designserver/auctions/maildirsize
./mail/designserver/homemedia/maildirsize
./mail/maildirsize

I went ahead and deleted the file to fix this issue.
root@vps [/home/designse]# cd mail/
root@vps [/home/designse/mail]# rm -rf maildirsize
root@vps [/home/designse/mail]#

Now all stats shows right details