Hmmmm...I hate to say it but it doesn't sound good. I kinda went throught the same thing (it took me about 4 tries on Nessie
) Anyway, both my NPCs got spooked when I went into the Rapax Rift (cowards)...so Vi told me she would meet me back in Heli's bar.
I figured I'd leave her there (hey if she ain't gonna follow me into hell then forget her!) About 4 hours later and sans NPC's (I get sidetracked easily) I found Grumph just by exploring and to shut his whinny a$$ up, took him back to the umpani base. I made my way back to Heli's (finally) and Vi was there...maybe it's a bug.