Mailbox overquota block POP on outlook

Hi all:
One of my coustomers have a extrange problem. He has a 15mb mail and pop3 account, who uses to get overquota.
Problem is that when the account is overquota, he can download ( and erase ) any mail form outlook client, so he can´t clean their mailbox, and get below quota again.

Anyone have same problem ?

thanks in advance.

 

Silver_2000:
Yes, he can do that on webmail, but problem is that he cann't use that.
As I understood, if your mailbox is full, you cann't get new email, but ( once your mailbox is full ), when you connect throught POP3, you delete email, so mailbox get on quota again.
Problem here is the lock of POP3 use if mailbox is full. I cann't think in a good reason to do that.

Thanks in advance

 

Mailserver: dovecot
cPanel 11.24.4-C34437 - WHM 11.24.2 - X 3.9

Thanks in advance