Has anyone been having problems with it not firing at all? When I received it, I put a mesh wick and 28g Kanthal 3/4 wrap on the top, and put in a fresh AW 18350, and I felt the bottom section heating up, but the coils didn't heat at all. I tried several other wick and coil materials, tried an 18650 battery, and even tried pulling the bottom spring up to see if it would make better contact, but nothing seems to be heating the top posts. Is this just a dud, or is there a fix? Sorry if this might have been addressed before, and thanks for any help.