I have one user who has problems with GW 2012 SP4 access on Mobile device via IMAP

everyone else can !

user login is PHILIP but couple of years ago his preferred email was changed to Phil@ - still login as Philip

When I setup the Pad (Android) - it automatically selects his login id as Philip and I can enter rest of the details
some emails are downloaded - i.e. up-to Dec last year & no new emails !
I can send OK from the account

From Consoleone I've run the Analyze/Fix on the mailbox - no luck

Won't authenticate if I use Philip (which works in GWClient & Webaccess as user name but either Phil or his full email address works fine!
If I try to use phil in web access its rejected (philip is the real username!)

Data is on Linux partition & users can't access it so I can't run the Standalone GWCheck from the Workstation !

Any ideas ??