Email on iphone stopped syncing with comcast email

Suddenly, my comcast email on my iphone mail app has stopped syncing.  After I went through all of the steps of deleting the app and re-entering all of the imap and stmp information, the mail started to update again, but uploaded over 700 emails.  

Is there a way to get the phone email to sync with the email on my computer browser?  Or do I have to manually delete all the emails that were previously deleted?

I also want it to continuously sync so that I do not have to go through this laborious task.