It could very well be that he didn't know about the cam gears - I would wager they never pull them down to do failure checks. The returned ones are probably the ones you get parts off.
No one would ask for a cam gear because 90% of their customer base would not pull them apart, most fail inside warranty and are returned, and if fails out of warranty - any service centre will treat it like its got corona (which I suppose can be a new version of avoid like the plague)
How angry is your mate with them? If I had pi**ed $2500 up against a wall, I would be fuming
