What version is this, EX, LX ?
Is it possible to get inside the vehicle and remove the rear hatch plastic door cover by chance so you can access the latch or switch assembly? On this type of issue there are no clear cut instructions, I am sure it;s frustrating and this may require Dealership expertise to get it open.
Is this a push button style door release? I looked in the wiring diagrams and did not find a rear latch electrical component.
Man that is a tough one, what happened then is the ROd that goes from the rear lock to the latch open came off and now the latch will not open. Very tough situation. The lock itself is bolted from the inside, there is no way to pop it off without doing major body damage. To be honest I think your only option is the DEALER, they most likely have a way to get it open. The lock is bolted from the inside, and the rod to open the latch came off.
Man, the only way is if you could access the latch itself from the interior. It's not possible to take the lower trim off the interior on the body and get at the latch or remove the rear panel? Hmm, this definitely worse case scenario, without damaging something there is no magic answer on this issue accept the DEALERSHIP. This time I am afraid you have no choice. The piece that releases the latch is on the latch itself, maybe with a curved instrument of some sort you could reach up inside the latch from underneath the door and push the release, that would be the only way.