My wife's Galaxy Note 5 just had a melt down sounds similar to yours. The phone locked her out after using the thumb print fuction...wouldn't take her passwords and I spent over an hour on the phone with techs from verizon and samsung. We had to go in and change passwords and do a factory reset on the phone. Now, due to a security function of the phone, we have to wait 72 hours before the phone can be reactivated...that is..if it does reactivate.....not a happy camper with samsung right now. We rely on our cell phones for everything. We don't have a land line and my wife uses her phone for work and now is basically out of touch unless she's in the office...Well this sucks....