I never have my phone delete email from the server but the Droid 2 seems to do it constantly. I have never had this problem with any other phone. Is there a fix for this or a known work-around?
Try another email app. Which is more important: having your mail be deleted or using an app that you like the looks of?
Or, as an alternate, manually set the mail app to use IMAP. Comcast mail can use IMAP: Using Email Client Programs with Comcast Email , or this page should help: Switching Email Settings from POP to IMAP - Google Nexus
This will keep all of your mail synced between all of your devices. I strongly suggest not using POP3 for anything if you can at all avoid it.