The closer they are to the ferrule the tighter the grain and harder to pull, without a retaper. The real bad one I mentioned was farther up in the open grained area of the shaft, and not all the way around, just 1/4 of the shaft, I've pulled several rings that went all the way around in that area simular to the one you mention, but not a good location where yours is at. If you have to replace the shaft, ask the guy if you can keep the old shaft, and you can use it to practice retapering By hand, Mistakes are how I learned to pull dents and retaper at first

. a wood lathe and a set of calibers. I do them alittle different now, but that's how I learned. I was lucky enough that It was My own shafts though, and I learned that way before trying it on a customer cue when asked to do It. I do feel your pain, had a few hard lessons Myself, unfortunatly it really does go with the territory, and is all part of the learning curve. If It can happen, there's a good chance It will. It makes you better, and more aware of what you do in the future though, if there's a good side to be found in it. It more then likely won't be the last time something goes wrong.
One of the most important parts Is being a stand up guy, and doing what you already are by replacing It. If it were something tricky that you were not too confortable with doing, they talk you into it anyway, and you forewarn them you'll do your best, but may be a bad outcome, and can't be responsible, then it might be different, altough still would'nt feel right, and i don't even like taking chances for that reason. In this situation though, when it was unforeseen, and unmentioned beforehand, the only right thing is to replace It, unless the shaft is too big for him, a large dia to begin with, and he does'nt might a serious retaper. I'm sure he was use to what dia he had though. Unfortunatly have to do what ya gotta do.
If i could help you out i would, but don't think I could pull this one off, by the sound of what you have there. I just did another long one near the ferrule, no where near that bad, on only one side of the shaft, and took 2 days on and off labor to pull out. a new shaft would have been cheaper or the same price, even though I got it out. Greg