wi-fi is not working. how to repair it?

the phone has wifi problem that is activated each time the phone is turned off and turned on automatically

"Even I'm facing the same issue. when I switch on wifi..... Phone hangs and start keep on rebooting.

When I visited Sony service , they said it's the motherboard compliant.

This is what I got answer from Sony service center.

Bloody Chinese Mother f-ckers."