My galaxy s5 is locked up with a fingerprint scanner and it won't let me do my fingerprint no more all it will let me do is the alternate password and I don't know it. I DONT KNOW WHAT TO DO HELP ME PLEASE!!!
Your best bet would be to reset the phone to its original factory settings using a computer and Samsung Kies. Alternatively, you may also use Google Account Recovery which would allow you to access your phone and possibly change your password.
Or bring the phone and a photo ID showing that the account is yours (or bring whomever's account it is with you, with his/her photo ID) to your carrier. They can unlock it.