I have an iPhone 4S and have lost the ability to connect to wifi it is greyed out and won't turn on I have tried restoring my phone as a new phone resetting network settings etc it came back for like a day and has now gone again any ideas how to fix this?

This is most often due to hardware failure of the WiFi Chip. The steps you have already taken are really all you can do without replacing the WiFi Chip. If there is Warranty or AppleCare Coverage make Genius reservation or set up Service and take or send to Apple for resolution.

Wi-Fi or Bluetooth grayed out

Click on the link provided and follow the troubleshooting steps.

I too have same problem. The helpline guys told me that its a hardware problem & can claim for a new phone since its on warranty but i bought my phone in Kenya & now i live in india ,i really dont what to do???

If it's a hardware problem, you take it to Apple or whomever in your country provides hardware support.

Note that warranty and support are ONLY valid in the country of origin.