Email sync

I took delivery of my first blackberry on monday, so im not up to scratch yet and this problem i cant seem to work out.

Basically when i set the email up it downloaded all emails from the server (yahoo), read and unread, just as i wanted it to do.

Unfortunately the phone developed a fault and had to be exchanged, which i done today. Ive set everything up in the same way i did before, but it wont download any emails from the yahoo servers to my handset. I have an active data connection, also wifi, bbm works fine as does wap.

I have resent service books and done a battery pull which hasnt helped

Can anyone tell me how to sync my email so all messages appear on my phone as they did on my first handset?

You won't get emails that were sent/received before you set the email address up on the device.

Are you saying that when someone sends you an email today, that email message does not get pushed to the device today?

No not new messages, all of the old read messages. The first handset i had (the faulty one i exchanged today) did actually download all old emails

Thinking about it, the messages all did initially show as being unread, even though they were read within the web based client.