You shouldn't have to change to IMAP. If you're not seeing incoming mail via your control panel mailbox, there's something wrong on LP's end. Any chance you could have a friend email you and let you know if they get a bounce message back? Don't post your address in public here.
Check for any broadcasts about your server being down for upgrade or restore -- usually the email will be down for a while and is queued up (although a few days is rather long for this). It should come flooding back in once the email service is restored.