Shower riser spurting water from fitting

I'd really love some suggestions! My new tenants called because the riser on the lovely new clawfoot tub is streaming water out of the top and bottom of the fitting between the two lengths of riser. My contractor who did the work (and apparently didn't test it) is out of town and unreachable. Last night, I disassembled as much as I could, rewrapped threads with Teflon tape and tightened things down more than they were. The problem, though, is that I can't remove the problem fitting! It's smooth and there's no way to get leverage to remove it, so it's still spurting water. My questions:

1) how do I remove this fitting? Is there a particular tool I need that's secret to professional plumbers?
2) why in the world would water be spurting in a steady, projectile stream from both the top and bottom of this fitting? I can see plumbers putty on the top threads and what looks to be Teflon on the bottom. Could it simply be the wrong fitting? (In the image, which for some reason is rotated, you'll see that I put some caulk on the threads in a desperate attempt to subdue the stream until I can fix it...)

Thanks!

Strap wrench. Try a thick pc of rubber or cut a piece of hose to wrap and protect the chrome. use less tape you only need a 2 or 3 wraps. . tape pushes off the joint if you use to much rather than getting captured between the threads

i use a 1/8'' thick piece of leather, wrap around the pipe and use a pipe wrench """"GENTLY"""