Both key fobs will start vehicle, but neither will function to do anything else now . . . Lock or unlock doors, open hatch, etc. Batteries replaced. Can they be reset? Volvo dealer service is unable to fix.

 

They need to be replaced if they have been tested and are not sending a signal.

 

Unusual for both not to function at all. I doubt it is programming. I would double-check battery type, battery insertion (polarity) and measure the voltage before assuming they are trashed. Also check the keyless remote antenna inside the car. I believe it is hidden behind the sunroof. A wire may have loosened, or there may be a fuse for it near the glove box as well.