wifi is grayed out
Hi, just today my iphone 4s will no longer switch the wifi to on. It is grayed out. I've contacted AT&T and they basically said that my coverage expired 20 days ago and I am out of luck. I have tried all of the restart functions. AT&T said the wifi chip being defective is common among Iphones. Any ideas would be appreciated.
iPhone 4S, iOS 7.0.4