Keyless chuck is stuck open

That can happen if the jaws inside the chuck, usually 3 triangular pieces get jammed together. With chuck facing down tap chuck several times to loosen jaws. If that doesn't work spray a small amount of WD-40 into chuck and try again

Okay... I've tried that, and the **** thing will NOT budge. There should have been an instruction manual with the product. I had watched my dad with many different drills, and all of them have keys, but they no longer work. I've tried charging them for days, and they no longer hold a charge. To make matters worse, they don't make the drill anymore either.
So, my first drill is this Black & Decker cordless drill, model number SS12C.
The chuck is open, but locked, and it won't twist or turn at all so I can put the screwdriver bit in, so I can use it. Put in some WD-40, and that hasn't loosened it up either.
Any other ideas? I'm going to take it to Lowe's (where I got it), to see if they can get it un-stuck. I've tried wrenches, vices, and everything I could to get the chuck operational again.
Sincerely,Brian.