As far as automatic update, the iOS cannot be updated without user intervention, so it could not have been automatically updated.
You need to provide more information about your mail. Does this mean you cannot access the Mail app, you cannot download mail, or what? Not sure why you cannot access the cookies setting in Safari. Go to Settings>Safari>Block Cookies>set to what you want.
Problems with 3rd party Bluetooth devices, such as car audio, etc., generally has to do with vehicle manufacturers not providing updates to match the current Bluetooth stacks that are found in today's phones. You can go into the phone and remove the pairing for the car, and then go into car settings and remove the iphone. Then put both devices back into pairing mode and attempt to connect them again. See this support document http://support.apple.com/kb/TS3581