I'd try an Oxy-acetylene torch with a rosebud tip. Try to evenly heat the outer circumference then tap with a hammer gently to get them to break loose.
If you can do it, sometimes with the e-brake released, rocking the car back and forth front to rear (easy to do with an automatic; tougher with a manual) will cause the shoes to let go. Once you free them up, pull the drums and take a look to see what the problem is.
Pull the little rubber plugs in the backing plates and back off the adjusters, if you have not done that yet. This should allow the shoes to retract. Then take a bfh and tap on one side while pulling opposite with your hand, going around the drum. If it rusted on the lugs or at the center, WD40 it, and tap a lot.
Worst case, you can cut the drums off with a torch, and just buy new ones.