rear hatch will not open
Too bad. Won’t open with the electric release? Or the key? Or both?
What happens when you try to open it? Do you hear any noises? Have you checked the fuse? Does it help if you push the hatch in when trying to release the latch?
Have you had recent rain, and then a hard freeze in your area?
I once experienced the same problem as the OP under those conditions, and when the ice on the door seals melted, everything was back to normal.
It’s old enough that the latch mechanism might need lubrication, but we can’t help you unless you give us more information.