unrecognized message, now all locked out I allowed my nephew to play with my Samsung tab 3 and it is now saying that I have accessed an account without being authorized and is asking for a password that I have never set, what can I do, without doing a factory reset?
That sounds similar to cryptolocker, without the paying to release your device. Try booting in safe mode(look up how, it varies) and taking off what your child used.