my iphone 6 freezes when I have wifi turned on

I have an iphone 6 and after updating to iOS 9.3.3 my phone started freezing when the wifi was turned on. I have tried it on other wifi networks and still have the same problem. I have also contacted apple and went through a lot of troubleshooting with them, and still have not had any success. I have wiped my phone using itunes back to factory, I tried resetting the network settings too. This is a photo of what happens sometimes too. I am not able to even turn the wifi on. It is just blacked out. This photo shows how the wifi will just grey out and cause my phone to freeze. It won't switch over to network. Thanks in advanced for any help!