Wifi Iphone 6 plus gold 64G Viettel !

My Iphone 6 plus dim switches, do not turn off the open. I tried resetting the network settings. Has reset all settings. Tried to restore the IOS 9.2. All are irreparable. Then I decide to take the warranty, but rejected baseless! I want to complain to Apple but I can not speak English! We hope to help!