iPhone 6s plus camera is black screen and the flash light doesn’t work either why

If you already tried (to no avail) all the steps provided in this support article:--> If the camera or flash on your iPhone, iPad, or iPod touch isn't working , I suggest that you contact Apple Support directly, using this link:--> Contact Apple for support and service , or make an appointment (*) and have your device inspected at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> https://locate.apple.com/choose-country-region . After checking it out, they'll give you all the available options.

Regards

Giulio

(*) You can do it:

• Online:--> Genius Bar Reservation and Apple Support Options - Apple;
• Contacting a local Apple Store or AASP among the list provided above;
• Using the "Apple Store" app, available and downloadable from AppStore.