Mail account's quota used but no email

hi,

i am using cwp7, some email accounts quota is used even though there is no new email at webmail, and when i check doveadm at console i got this:

doveadm quota get -u xxxxxxx
Quota name Type    Value  Limit                         %
user       STORAGE 72052 256000                        28
user       MESSAGE   233      -                         0

so how to clean that storage and usually what is that storage for?

After recent update on CWP the email account usage are showing out of allowed space for each account, there was issue in CWP and it is a BUG. how these email users can use more than allow space for their email usage ? IF CWP is working fine this will not happen .From our experience CWP always have BUGS and it was not resolved or sorted yet.

We are facing same issue see the screenshot.
http://prntscr.com/16puu6e