IMAPD attack

I'm under some form of a hacking attempt on IMAPD (143). CSF is doing a fine job of blocking them, however, it's also blocking class B subnets (intentional), so eventually, I know that this will impact one of my offshore users. As I believe that I'm the only user on our server utilising IMAP, I've temporarily blocked port 143 in CSF, to everywhere barring our office. A consequence of this means that I can't receive my emails on my phone, outside of my office. Is it possible to reconfigure my phone to operate on POP3, but leave the emails in situ, so my office PC can still get to them on IMAP ? I know it's possible when using just POP3. The phone receives the email and leaves a copy behind, office PC then downloads the copy. Just not sure how this will work when using IMAP in the office and POP3 on the phone. Android Phone by the way.