Also what are their colors? Sometimes that can matter. Are they pedigreed so that you have a degree of certainly about their genetics?
I have read that certain breeding pairs just aren't compatible and sometimes you have to try a different chinchilla.
If one of them is sterile this could also explain it. There are veterinary tests that can be done to help establish that. If you haven't had your female examined yet for breeding capability you may want to have that done as well.
For breeding the cages should be in a very secluded place where there are no noises or activities that can stress them out. Room temperature should be above 60 and below 73. Most large scale breeders use artificial lighting on a timer so there are 12 hours of daylight and 12 hours of darkness.