Called back and if you don't use the phone they called you get dropped. It's a scam www.heycosmo.com is the website. Just incase you all wanted to know it. Now you have the info do what you want
same as most... 3 rings and hung up, no mssg, will add them to block list but if it's searching for active cell to spam by text no doubt another line will do that grrrrr indeed