Each of my eGo-T’s are no longer working – flashing 3 times and 20 times

Each of my eGo-T’s are no longer working – flashing 3 times and 20 times I’ve two eGo-T’s that are defective. On my very first eGo-T the issue takes place when I put a cartridge in the battery pack (that will be completely charged). Whenever I screw within the cartridge, really gradually and carefully, and…