Called, Did not leave message.

I am in the ER due to a medical reaction and they keep calling!

My phone rings and I drop what I'am doing to pick up the call.........son-of-a-b_ _ _ _  I exclaim!!
650-257-1301 is at it again. I have tried dialing back the annoying caller but there is only silence and not even a ring tone.
Who are these a_ _ _h _ _ _ _ and why do they do this??  I have tried blocking numerous phone numbers but always a new one crops up. What can I do?

Nanne

Hangs up after asking for me by name