Iphone 6 completely dead after one week. it wont charge and i have tried three different chargers that work with another phone.

Connect it to the wall USB adapter for 15 minutes. Then hold the HOME and SLEEP buttons at the same time until an Apple logo appears.

When the battery on an iPhone is completely drained the iPhone will take some time before it responds when connected to a charger. Do as Lawrence Finch suggests and connect the iPhone to the charger that came with it and make sure that is plugged into a known good wall outlet. After 15-30 minutes reset the iPhone. Press and hold both the Home button and the Sleep/Wake button continuously until the Apple logo appears. Then release the button and let the device restart. You will not lose data doing this. It's like a computer reboot.

If the iPhone restarts let it continue to charge until the battery is 100%.

If the iPhone does not restart make an appointment at an Apple Store to have your device examined by a technician. Or contact Apple Support. Be sure to back up your device before taking or sending it to Apple.