My wife's Iphone6 is going crazy. It's getting very hot when you use it, and by use it I mean message or try to call. It won't receive phone calls and texts are coming in 30-45 minutes after someone sends them to her. It won't sign into iMessage it just keeps trying. Somethings you check messages and it shows none at all, completely blank. It's running IOS 9 and I've reset network settings turned it ff and on. Should I try to restore as new or try to go back to 8?