Rang the phone incessantly.  Every time we answered, there was a recorded message that said the call was from a Sprint customer with a text to landline message, press 1 for the message.  There was no message after pressing 1.  The next message said press 2 to leave a voice message or 3 to text.  I hung up and the phone rang right back, time after time, with the same recording.  Finally, we have to leave the phone off the hook and block the number.