I'm not able to switch on my Wifi The icon looks hidden

Try this If Wi-Fi is grayed out or dim on your iPhone, iPad, or iPod touch - Apple Support

Hi Turn off your router for 20 /30 seconds when it's back on go to settings on iPhone down to reset Reset network settings After reset enter your router wireless key.

That should help.

Cheers

Brian

Hi there,

What you can do is try to reset your network-settings.

If that's not working try to restore your iPhone as a new one via DFU-mode.