Every time i turn the wifi off it would turn back on by itself after a few minutes, any help!
Go to Settings/WiFi/Advanced and make sure "Turn On WiFi Automatically" is off.
Go to general management in settings and tap reset accessibility settings, reset networks, and then reset settings, your phone will restart. you will have to set up your phone settings and put your password in again. But, it should help.
More than likely the automatic wifi setting like the other post mentions. That makes wifi turn on in trusted areas to auto connect like in your home.