Mail problems with Mustang

[binarybrains]

Hello. I have a reseller account in mustang and have experienced ocassional mail problems with e-mails: bounced, not received, unable to send, outlook doesn't get them properly. Today I got a call from a client, www.edithscabo.com and I couldn't tell him exactly what's going on. also i have lost hosting clients because of this. Can you tell me what's wrong and how to prevent it?

Example: (says inbox is full, but it only has one message)

 
This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of its recipients.
This is a permanent error. The following address(es) failed:
reserve@edithscabo.com
mailbox is full: retry timeout exceeded
------ This is a copy of the message, including all the headers. ------
Return-path: <ap@binarybrains.com>
Received: from [201.110.79.230] (port=63860 helo=lunchbox)
by mustang.websitewelcome.com with esmtpa (Exim 4.52)
id 1GLMA0-0000EZ-IR
for reserve@edithscabo.com; Thu, 07 Sep 2006 10:51:24 -0500
From: "Alberto Perez - binarybrains.com" <ap@binarybrains.com>
To: <reserve@edithscabo.com>
Subject: mensaje
Date: Thu, 7 Sep 2006 09:51:24 -0600
MIME-Version: 1.0
Content-Type: multipart/related;
boundary="----=_NextPart_000_0016_01C6D263.30596CC0"
X-Mailer: Microsoft Office Outlook, Build 11.0.5510
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1807
Thread-Index: AcbSlXjWests+AW6QTeNhbwlG8F1bA==
This is a multi-part message in MIME format.

[Serra]

The mail box is full.... Really, that is the problem. Check the mail box and click "Show Space" and you will see it is full.

Just give the mail box more space or have your client empty it out.

If the mail is being forwarded, then delete the mail box, you don't need it.

(if the client doesn't need it because they don't check it or store mail there)

[binarybrains]

now clients are reporting me problems in all of their e-mail accounts in
elfaroviejo.com.mx and thetrailerparkelfaroviejo.com.mx
but their inboxes are empty and the mails are still bounced back

how can i solve this?