Hi, first off welcome to VU!
The thing about the CLK and other ego or "self contained" batteries is they're consumable and have a service life. If you've switched chargers and that didn't solve the problem the battery might be at the end of its like or the chip inside of the CLK that regulates everything might be going out. The batteries inside of them are rated for so many charge cycles like any other battery and it could be anywhere from 250-500...if you bought it in september you shouldn't have reached that number yet but sadly, even Innokin who I think makes the best eGo style batteries, is going to have units that burn out quicker than others due to mass production and some lesser ones slipping threw QC. I've never had a CLK but I went threw 2 dozen ego (10 of them were Innokin brand,) batteries over six months...some still work today as good as the day I bought them, some malfunctioned and died, and some died the first time I dropped them and they blew apart.
I am sorry for your issues, you can try the vendor you bought it from to see if they can help you but since you've had it for four months you might just have to buy a new one. It sucks but they're not made to last forever. I hope you get it figured out and best of luck.