If you pay for the insurance or damage waiver on the rental car when you were not at fault can you get reimbursed for that expense If so how?

Yes, I am going on the following assumptions to answer your question; You rented a vehicle and took out the damage waiver, (did you have insurance on another vehicle? If so that changes a few things) had an accident in this rental vehicle that WAS NOT YOUR FAULT AT ALL. You (or the rental company) could file with the 'At Fault' party. Some rental car companies will chose to use their own carrier for speed, so they can get that vehicle back on the road. In that instance, (and apparently that is what happened) once the final payments have been made, their insurance company should file a subrogation claim against the at fault carrier, and recoup all money paid in the claim including the deductible you paid. And in turn will return that to you. If the other party is not insured there will still be a subrogation claim, but this generally takes a lot longer. Let me caution you though, this is under the assumption that

a) there was absolutely no negligence attributed to you

b) the 'at fault' driver had insurance.

c) no dispute between the carriers as to liablity. You should be kept abreast of the investigation, and subrogation claim, if you have not been contact the insurance company that is handling the claim, if you do not have their information, call the rental car company and get it from them. If you would like to provide me with additional details surrounding the facts of loss etc, perhaps I could be of greater assistance to you, and would gladly try.... Good luck !!