You had a cam break, and did you get anything back from the person you purchased it from?
I have seen a lot of single cam cams break, many of the times sheering at the cam gear, A bisi turbo billet cam, comp/zex cams etc..
The only ones I have seen not break are s2 and one other one, I cant remember right this second.
I think a lot of this has to do that a lot of people will piece together the motor, instead of bringing a complete running motor to be built. Its hard to say who is responsible.