mail client only allows some mails to pass through for yahoo

Hi guys,

I have a macbook pro 15 inch, the early 2013 model.

Software model:

OS X 10.8.4 (12E55)

Starting from June, my mail client had been messing up real bad for yahoo mail.

Some of my mails started to randomly disappear; upon this, I searched up the forums and rebuild my entire mailbox. Junk mail filtering was also disabled (since it had this nasty habit of putting everything in junk mail, especially the important emails regarding work...somehow)

Anyway, the key issue currently is that it only allows some mails to pass through.

For instance, from the web client, I may find that I have 3 emails from 10 am to, say, 4pm. However, the mac mail client may show only 1, or even no mails at times. And yes, I did check the Activity window to see that the mails had finished loading.

Sometimes, it shows incoming mails, but after downloading, it does not appear either.

I had frequently missed emails from friends due to this; as a result, I had been using the web client which is rather inconvinient due to the slow internet speed during peak period.

This is kinda weird. Please help me out! =)