I have a 2008 Hyundai Santa Fe with a stuck passenger door. It just stopped working. You can pull the handles inside and/or out and the door does not open. I think they must use the same wimpy spring as the Kia does. I've tried to pull and push on things inside the door using a bent clothes hanger wire, but so far nothing. I just reread all of the comments and will try to kick open the door from the inside with the handles held in open position.
The dealer said $300 not including needing to destroy the inside panel in order to remove it. For now I would rather explore cheaper options as it is not urgent - but would be VERY nice....