The phone will not turn on

I have an apple iPhone 6 that ive previously fixed. New screen new battery and new front facing camera ribbon cable. but with all said, My phone fell off my lap when i got off my vehicle (small drop) on concrete but i had a otter-box on. The phone was fine but afterwords the battery got stuck at 80%. i powered the device on and off but the result was 17% left! i charged the phone but it wouldn't charge and went down to 1 percent. i tried charging it over night using all apple cable and power block but the next morning it was at 1%. then suddenly it started re starting by itself then came to the point where the screen turned gray and shut down. after that the phone wont turn on or charge. already replaced the battery and nothing happens. no apple logo... i need help soon