iPhone 6 stuck on activation lock

I had recently been given a phone but once I had reset it (the owner had logged out of the phone) I get stuck on the Activation Lock screen. The owner says that was the only Apple Device they had. I try to login with my own Apple ID and it doesn't allow me to. I even try to use Quick Start with an iPad that I had setup, and still get on this Activation Lock, I even tried using Apple Devices an it shows "An error occurred while trying to activate your device (Eject)" Any help will be appreciated.