My power button , volume up and down button,ringer&silent not working.

Hi Alade,

Since all of the components you've mentioned are interconnected on a single flex cable, it's pretty obvious where the problem lies. That cable also holds the rear microphone, the one used when you record videos with the rear camera, so I'm betting that isn't working either.

Here's a picture of the part.

I can't begin to guess why that particular assembly on your phone has failed; has anything happened to it recently such as being dropped, getting wet, etc?

Regardless of the cause, the best chance you have of fixing the problem is to replace that part. You can pick it up all over the place; Amazon, eBay and AliExpress all carry it for under $10 USD.

Unfortunately iFixit doesn't have a guide to replacing it, but there's a French site called SOSav that does. Here's a link to it.

Power, vibrator, volume, flash, microphone cable iPhone 7 Plus repair - Free guide - SOSav

If that part doesn't turn out to be the problem, then that only leaves a problem with the connector or circuitry on the logic board itself that would require board-level repairs; those kind of fixes take specialized equipment and expertise that is beyond the capability of home DIY repairs.

Best of luck with your repair; let us know what happens!