whats wrong with the phone? does the screen show anything when you charge it? do you see any lights when you plug it in, have you tried turning it on and plugging into a computer to see if it shows up?
i believe the lcd is going bad, i saw this same exact issue with a customers phone, i thought it was the proximity sensor so we took off her tempered glass, it worked then it came back right away. my conclusion was she had either a faulty motherboard or faulty lcd
you have to purchase a google unlock go on ebay and look up FRP LOCK or google unlock and contact the buyer and let him know what phone you have if that doesnt work for you check youtube for a google lock bypass for your lg. ive done in without purchasing anything on ebay
turn the phone off then turn on while holding both power button and volume up, and home button if possible continue holding untill you see a menu appear and choose factory reset Update (06/29/2017): Volume Down + Home + Power button for a few seconds. You can release held keys when you see the Android Robot. To enter the Recovery Mode hold down the Power key for a short while. In this step use Volume buttons to select "wipe data/factory reset" and tap the Power button to confirm.