HI! my iphone 6s randomly shut down by itself completely
HI! my iphone 6s randomly shut down by itself completely even if it's sufficeint baterry power. I went to the service twice where they took the baterry tests and said that everything is fine and they have returned. But the problems have not disapper. I can trust if i put an alarm for example because maybe overnight the iphone randomly turn off. Please help
iPhone 6s, iOS 9.3.5