Unfortunately, clones can be hit or miss. I'm not familiar with Cigreen, but I'm aware of people who have had good luck with Infinite and EHpro; although, as I said, it's hit or miss. I save up to buy authentics, but even then I do research on where they are manufactured, since some of them are still mass-produced with questionable QC. What authentic device have going for them is usually more vendor support.
I have an authentic Svoëmesto KFL+ and a "Black Edition" clone (which isn't black lol!) from Custom Mod Creations. Side-by-side it's obvious the Svoë is better made, but both work well and if money is tight the BE is an acceptable substitute, based on my experience. Aside from quality and customer support, my reason for buying authentic devices is to reward those who have put the effort into original design and development. However, I'm not one to condemn clones in general, since some of the authentic prices are pretty steep; plus, clones often lead people to buy authentics if they like a clone, but want one of better quality. Although I do stop short when it comes to batteries and chargers. I firmly believe people should get name brands of things that might catch on fire.
Hopefully, you bought the devices you are having trouble with from vendors who will stand behind what they sell. Even FastTech supposedly has reasonable customer service, albeit slow. If you aren't already verified I highly recommend you do it. I have bought several authentic devices off the classifieds.