The B version from FT is different then the one Gearbest sells, the first listing from FT is same as Gearbest, and the same one you & I both have. Mine does not have any sort of o-ring on the chimney either, and it works fine, I've had no leaks. my 22mm ring is just fine, is your threading messed up? I noticed it is quite fine threaded and takes a little fiddling to get it started.
As for the 510 pin, mine could due to be a little longer, but it works fine, I added a couple o-rings on it to stabilize, and prevent it from turning in when screwing it on a mod.
Good luck on tickets with gearbest, my last experience with customer service was about 3 weeks to even answer, then a few weeks between each response.