Synology Crashed Volume (Raid 5)

I'm panicking here, my Synology DS1512+ has been running for 4 years fine it has 5 3TB WD Reds in it in raid 5. The other day the volume became "degraded" So I rebooted the NAS and the volume became "crashed"
.Testing proved that the drive had 1 "Pending sector reallocation" and the NAS didn't do so well at reallocating the sector. All the drives (4 definite) (1 possibly) are healthy. I cannot get the array back online, I've contacted Synology support, but I know how good you guys are at doing things like this, and Wendell and his data recovery.

Thanks, all help is appreciated.