How do I get these d#!@m tiles off the wall?

I'm having new countertops put in and I've got to take off the tile backsplash down in the kitchen. Problem is, they're on there GOOD! I've got a dremmel tool with a grout blade, I've got a pry bar and a hammer - nothing is working. I've actually poked a hole in the drywall in the shape of a 4x4 tile. Even if the installers decide that it's ok, they can make it fit...too late, I've chipped and cracked the remaining tiles in my struggles. Grrr.