IOS10 seems to have a lot in common with Windows 10. Both were not particularly wanted and both have done badly.
IOS10 installation wiped out everything in iTunes off the handset. I didn't even realise until the phone 'rang' with an unrecognisable pling-plong-pling. Ringtones had gone too.
Any attempts to resync things are met with a message 'The iPhone cannot be synced because it cannot be found'. It is of course plugged in to the computer at the time.
Is it time to go back to Samsung?