rousseau

Got a pair of Centaur carbon 10-speed shifters in a trade for a saddle a few months ago, and just sold them recently, but my buyer mounted them on his bike and found that the rear shifter only shifts three or four times!

I had held them in my hands and clicked them when I'd first bought them (used), and they seemed to do 9 clicks up and down, but having just received them in the mail from my erstwhile buyer, the rear shifter does indeed only shift three times.

Any idea what part might need replacing? What kind of labour charge do you think someone might charge for this?