I would call the fire department like tulosai says. If they can't help; they may know who can. I would do this sooner; rather than later. Perhaps you can call on behalf of the neighbors if need be?Someone really needs to go up and get the cat. At this point it's most likely the cat will lose consciousness before it falls down and that will be how it comes out of the tree. Also, it is definitely nearing the time it can no longer survive without water if it hasn't already reached it. Please call the fire department or someone else who can help.