Holy .... sticks.... after 2 days of owning my Stingray Black/copper and my Kayfun lite + v2, the first time i ever try my Kayfun on this mod and BAAAAAAAAM.... locked shut! Same problem as all of you guys... that damned AFC screw. So i thought id post here detailing how i fixed it incase someone else has been having this problem.......After some research i tried everything i could think of... i even considered using pressurized air to somehow push that screw back up...
What worked with me, surprisingly was a hammer! I tried everything listed here, Freezing, Dental Floss, brute force , Elbow grease, pliers, that jar opener thingie........ you name it, i tried it.
You can try any of the methods above they might work for you, for the dental floss, i wet it, fully saturating it with water then i rigged it to the door handle so i can torque it without using my hands. i got the damn dental floss inside over 4 times, i could feel it slip under that screw... tried simultaniesly pulling the topcap w/ the floss while turning the base... still no luck... After much suffering and agony, i tried the brute force method using pliers and tablecloth and rubber on the teeth, still not enough grip to pop it open.... and then a stroke of genius......
With just the topcap and the kayfun base, i covered everything with some table cloth for padding, with the topcap underside facing me, then gently kept tapping on the padded surface quickly, kinda like how a bump key would open a lock from light tapping of a hammer......it helps if you actually do all this on a bed or a soft surface to absorb the shock. and them Boooooooooooom pops out like butter, with minimal damage.... ....ING STOKED !
Hope this helps someone having this same issue, i just saved myself around $80 dollars

Good luck and be patient.. it can be done!