The first hour of a doubt

Write what you saw and when. If the device is still doing something you do not recognize, disconnect the network before switching it off, when that is safe for the people nearby.

Do not pay, and do not send the code the message asks for. Call a person you named in advance, not the number written in the message itself.

These are general first steps. A contracted response is written in an agreement, and this page is not an emergency line.