Go into your Google and Samsung accounts and log out any device you don't recognize as your own. Then go to an uncompromised device and change all your passwords - Samsung, Google and email (all of them if you have more than one). Get a new SIM chip from your carrier. Back up your personal files to a flash drive and reset your phone and install everything from scratch. It's inconvenient, but necessary.
There was no need to make two posts on this matter. Duplicate posts are not allowed, so please delete the other one, since you already have multiple responses to this one.
