MostApha, I feel for you! I hope this gets solved soon.
When I first received my Uma Poldiac, nothing would twist into it, not a single atty... they all rested on top. Tony had me take the topcap off, and then screw an old SS cartomizer into the backside. (OMG that sounds awful lol). Something fell out. Yay! A burr. I was then able to twist an atty into the connection, but only half way.

Whoa, this sux. So then Tony & Cloud instructed me to do the carto thing all over again, on both sides, both front and back. Still nada/ So, next, they instructed me to pull while twisting it in, and push while twisting it out, ... repeat as necessary. After about 5 or 6 tries, VOILA!! It's been perfect ever since. All my attys fit right in. I don't have the same ones you do, that's true, but I did have the same(?) problem with the ones I have. There was a big burr and when that cleared out, there was still a tiny microscopic burr or too tight of threading or whatever. I hope yours gets resolved soon.