New UPC internet, now, email doesn't download

Hi all.. I got new internet from UPC last week and everything works quite well, almost. TV works, Internet works, telephone works but email will not download on any device in the house (i.e. computer... multiple email programs and setup programs used, iphone or ipad, etc.).

I've spoken a couple of times to UPC and their standard answer is "we only support our emails" which seems to me is their way of dodging the question. After hours looking on the internet for solutions, turning on/off firewalls, trying various ports and settings, nothing seems to work.

Any ideas? FYI - I'm on a Mac, normally use Postbox as my email client but have also tried Mac Mail. We have a weird combo of Gmail, Yahoo and work addresses and none of them work.

Thanks,

Michael