yes I searched, didn't see this particular issue covered.
yes, I already contacted sprint (via chat), soft reset the phone, reset the mail app, updated my data profile, etc. I didn't call the 1-888 number yet.
Riddle me this - why do newly created / sent emails go out OK but only replied to emails get stuck in my outbox permanently?

I can create a new email to myself and in seconds it shows up on my desktop outlook client. If I reply to that same email, via my Instinct - nothing, drops into Outbox. If I reply to the email using my desktop outlook client, it's fine.
Using corporate OWA, this used to work OK but has been wonky for the past 1.5-2 weeks (not sure exactly when it started)
I do have my email log - some things look suspicious:
2010-02-25T09:41:22Z:1:CLNT: EVT_APP_SUSPEND event
2010-02-25T09:41:22Z:0:S7OnAppSuspend called
2010-02-25T09:41:22Z:1:NetG: suspended
2010-02-25T09:41:22Z:2:S7Cancel called but we're not busy!
2010-02-25T09:41:23Z:1:+++ PersistStatsForExternalUse: Setting system property - Calendar support= 1, err = 0
2010-02-25T09:41:23Z:1:I HaveMail is OFF and in foreground
2010-02-25T09:41:23Z:1:oem://mailto?new="0"&accounts="1"&popupAlert=false
2010-02-25T09:41:24Z:1:CLNT: EVT_APP_STOP event
2010-02-25T09:41:24Z:1:CLNT: Normal application stop
2010-02-25T09:41:24Z:1:+++ PersistStatsForExternalUse: Setting system property - Calendar support= 1, err = 0
2010-02-25T09:41:24Z:1:I HaveMail is OFF And in background But No New mail
2010-02-25T09:41:24Z:1:CLNT: SDAPI End
2010-02-25T09:41:24Z:0:S7OnAppStop called
2010-02-25T09:41:24Z:0:S7OnAppSuspend called
2010-02-25T09:41:24Z:1:NetG: suspended
2010-02-25T09:41:24Z:2:S7Cancel called but we're not busy!2010-02-25T09:41:25Z:0:S7OnAppStop called
2010-02-25T09:41:25Z:0:S7OnAppSuspend called
2010-02-25T09:41:25Z:2:S7Cancel called but we're not busy!
2010-02-25T09:41:25Z:1:S7CtxDestroy: Unloading.
2010-02-25T09:41:25Z:1:S7CtxDestroy: Unloading.
2010-02-25T09:42:26Z:0:S7OnAppStart called
2010-02-25T09:42:26Z:0:S7OnAppResume called
2010-02-25T09:42:26Z:0:Sync: no rollback required for 'mail'
2010-02-25T09:42:26Z:0:Sync: no rollback required for 'calendar'
2010-02-25T09:42:26Z:0:S7OnAppStart called
2010-02-25T09:42:26Z:0:S7OnAppResume called
2010-02-25T09:42:26Z:0:Sync: no rollback required for 'mail'
2010-02-25T09:42:26Z:0:Sync: no rollback required for 'calendar'
Any help greatly appreciated!