Email not working

Comcast email has been intermittent for multiple days. I just get the spinning blue ball when I try to open, close, send, receive, or add an attachment. I also can't move between inbox and drafts or other folders. Tried "chatting" with Comcast and they said it was a browser issue. It's not. I have the same problem on all browsers (Safari, Firefox, Google Chrome, and Internet Explorer) and different computers (Mac and PC). They had me reset my box but the problem continues. They say there isn't a problem on their end, but there's no other explanation for why my email won't work on multiple browsers and different computers. I can open and navigate websites without any problem. It's specifically a Comcast Email problem on their end.