Unknown caller. when you answer the caller hangs up. Call back you get "you were in a servery, but the time has expired, press 1 to remove your self from the list"
This happen to me about 3 weeks ago. I press 1 and still getting calls.
Their carrier is bandwidth.com, on that website there is a link to a Legal Page. Just below the section for the Acceptable use policy is a Blue Link to Report misuse.