I received a call from this number but didn't recognise it so I left it. Immediately afterwards (as in 3 seconds), I then received a call from 804-409-4424. This has happened a few times recently: different numbers calling straight after one another as if the same person is calling my number from some randomly-generated number at their end. Anyway, both blocked now, although I doubt that will stop them.

Called my cell, said Belmont MA, I did not answer as I didn't recognize the number.

called my business. went to ans. machine. didn't leave a message.  not the first time.  it's definitely a robot. spammer.

Called my celk, but no message left.

Scam. A woman robo voice pretends to have earphones off, then goes into a song and dance about a vacation deal and claim you have contacted them before. They use many numbers and constantly call trying to get you to say "yes" which they can record for nefarious purposes. They call my business non stop. I block one number then they go on to the next. Particularly bad when I am traveling. I have to answer as they are in an area where I have clients.