My 6 will not open or show a screen. Was completely charged and turned off. When turning in it flashes an apple and then goes to a very dark grey screen. Unable to get anything.

Make a backup if possible [Back up and restore your iPhone, iPad, or iPod touch using iCloud or iTunes - Apple Support].

Attempt to restore it via iTunes to factory settings if possible [Use iTunes to restore your iOS device to factory settings - Apple Support].

Test the issue. If issue persists, You'll need to contact Apple for your options. If within warranty and there is no physical damage or unauthorized service to the device, it will likely be a free replacement. If it is out of warranty or has physical damage, expect to pay $299 USD + tax. If there has been unauthorized service done to the device, expect to have to buy an entire new device at full retail price.

Woolmoon wrote:

ALso, I can't get into the phone to get a serial number so can't chat with Apple about this problem.

You can find the serial number of the device in multiple places:

A) Engraved on the back of the device is the IMEI number. That corresponds directly to the Serial Number.

B) On the box it came in.

C) If you made a backup to iTunes previously, you can find the serial number in the Preferences window, under Devices.

[Find the serial number of your Apple hardware product - Apple Support]

HOW TO GET TO PREFERENCES

MAC OS X: iTunes Menu > Preferences

Windows: Edit Menu > Preferences.