Hi, quick intro, I am 72 and have been interested in RC stuff for a long time with someperiods of absence. My brother got me going again with drones. not sure about others but I believe many companies are only interested in selling their products and their customer service is rubbish. I like to fix and build all sorts of drones so I am always looking for parts. I recently got a couple of 250 semi racing frames( my description) so I gathered motors, esc’s ect ect to do a build. In my research I came across KK2 fcs and liked the principle. So bit the bullet and ordered three, (there were no instructions)assembled the gear( using a tgy i6 tx and rx) found a good utube site and presto all looked good, got the active sign, hit the throttle??? And only three motors were active. Ok, pulled it down, resembled, put in other Kk2s .Same result. Back to research, to MAYBE fix you need to download this,this,and this, buy this and then do this. What the hell ( I am being polite)Surely they shouldn’t be selling faulty parts in the first place. After many emails the company told me they would give me a $20 refund and I could keep the Kk2s WHOOPIE. My build has been put aside for now, just got a very interesting fix, a under and over octo. This rant over