iPhone 6 not turning on

I've had this iPhone 6 since it came out and I just started reusing it a week ago. I turned it off the night before and when i go to turn it on the next day, nothing happens. The night before i put the phone into DFU mode and im thinking that the phone is stuck in DFU mode now and ive tried everything. I left the phone charging all night, replaced the battery, replaced power and home buttons, and ive tried hard resetting the phone by holding the power and home button together for 10 seconds and even up to a few minutes straight. Ive even replaced the screen too but still no luck. Plugged into itunes and its not showing up there. Please any help and/or suggestion would be great.