When you try to unlock with the power lock do you get any movement or noise?
If the button goes up there is one of two problems either the linkage has come off the latch or the latch itself needs replaced. Either way you will need to get the door panel off to determine which one! That of course is the hard part with the door closed. All you can do is pop it loose at the top and try to squeeze inside the door from the top to get it open. This is not easy to do, but it can be done.