I actually picked this one up, it was a Robocall letting me know that my student debt relief was flagged for a special promotional discount and to press 1 to talk to someone and 2 to decline the offer...... I have no student debt.
Its a phishing robo caller. Its designed to find if a random number they call is answered or not. The automated system gives a prerecorded message about a product or service and tells you to press 1 for more info or press 2 to be taken off the list. If you press either, nothing happens and it hangs up. You have now just confirmed to them your phone is answered and you get put on a list thats sold to telescammers.
If you call back, an automated system only offers you to press 9 to be taken off the list, then hangs up.