are you saying that email is deleted from the phone inbox without you doing anything? Are you downloading or removing it from the inbox on a computer? That's the limitation of the POP3 email protocol (not the app). POP3 email is meant to be downloaded and viewed locally and removed from the mail server (which is what the phone is looking at).
In the email app, look for a setting to 'Sync Remote Deletes' (or something to that effect) and uncheck it. if the standard email app does not have that setting, K-9 mail does.
Yes, deleted from the phone inbox...message is still on the server. I use windows live mail on my laptop for email on the Time Warner account and the emails in question are still in the inbox there, so they are not deleted from either (server or windows live) only on the device.
I have the device set to never delete from server but I do not see the "sync remote" option you describe (very limited settings). Maybe I will try k9 again with your suggestion...although I prefer the standard email client on the device...thanks for the advise
the windows live mail may be downloading the mail off the mail server (Time Warner) and storing it locally on your computer. That's how POP mail is designed. check for a setting in live mail to leave the mail on the server. TW may not like this and your inbox will fill up at some point and reject additional mail. if you log into Time Warner's webmail (browser), is the mail in the inbox?
The never delete from server setting is so that if you delete an email on the phone, it wont delete it on the mail server. K-9 mail has a setting to not Sync remote deletes. so when mail is removed from the inbox, it wont be removed from the phone (leaving the email copy on the phone).
also, see if TW offers IMAP mail settings instead. this will leave the mail on the server and any client just views a local copy (ie gmail).