ArmTwista™ - The Best Shower Arm Extractor Ever Made

Although it is a great tool, and the best I have ever seen for this single use application, it has so far failed to do the job in my case. And with the super high price, it was disappointing to not have the magic and joy happen, especially since it is the only time I will probably ever use it. I am not a plumber, but I have done my share of plumbing, including dealing with old galvanized steel, cast iron, and copper in home renovations, and modern plastics. The galvanized steel elbow is about 4 inches inside the old ceramic tile and solid plaster wall, and even after soaking the inside of the elbow with PB Blaster for 3 months previous, the broken shower arm ring seems to be rusted on with no release. It would not release with constant high force with a socket wrench, or with an impact driver. Maybe I should spend even more money and buy an impact wrench? How much force should be used before the elbow breaks loose from the other end? The actual dimensions are not listed on the website, and I had to email 2 times to get all of them. It is 6 inches tip to tip, 3/4" at its widest diameter (and 12mm hex male for any socket.) The ArmTwista is a beefy and extremely well made tool, and at the cost, it should be. I certainly am not blaming the tool for the rust seal of the broken shower arm ring. and my continuing predicament. I continue to soak it in PB Blaster, and wait, and will keep trying, as my only other option is to destroy the wall at this point. (Access is not available from the back side.) Any suggestions on a continuing plan of action would be appreciated.