[Dovecot] Imap Quota Exceeded - But Still Receiving Emails?

[Palatine Web Support]

Hello

I am trying to setup dovecot maildir quota, but even though it seems to 
be working fine, I am still receiving emails into my inbox even though I 
have exceeded my quota.

Here is my dovecot config:

plugin {
   quota = maildir:User Quota
   quota_rule2 = Trash:storage=+100M
}

And my SQL config file for Dovecot (dovecot-sql.conf):

user_query = SELECT '/var/vmail/%d/%n' as home, 
'maildir:/var/vmail/%d/%n' as mail, 150 AS uid, 8 AS gid, 
CONCAT('*:storage=', quota) AS quota_rule FROM mailbox WHERE username = 
'%u' AND active = '1'

CONCAT('*:storage=', quota) AS quota_rule

quota_rule = *:storage=3M

So it picks up my set quota of 3MB but dovecot is not rejecting emails 
if I am over my quota.

Can anyone help?

Thanks.

Carl