Why does my iphone 4s doesn't turn on its Wi-Fi?

My i phone 4s won't turn on its Wi-Fi, the Wi-Fi switch is gray all over and it won't let me turn it on, i repaired it at a repair shop so it was fixed but a few hours later it won't turn on again! The switch was full gray again and repaired it again and it broke again and so on and so fort so i'm asking you what's the problem and how to fix it so Please Help

You'll probably have to call apple & tell them what's happening, they'll probably send in your phone too fix it.
I know quite a few people have had that with their iPhones as well.