If the client refunds then yes.
How do you loose the bonus as from what your saying are they not one of your colleagues customers and your having to fill in for someone else who is now off?
I ask how can they be off and how come your the fall guy, just sounds to me like someone is taking advantage of you. How about the guy who was supposed to do the install actually does it and how does it effect your bonus when it was one of your colleagues who should have been doing such install?