Who called from 5702183030

This number called and left a voicemail. It started with a long pause then this lady says " Hello Crystal, How are you today?"  Then followed by another pause and hangs up. I'm very creeped out!

I forgot to mention that she said her name was Lou Anne.

My cell phone rang. I kept saying Hello-no one there-

Same thing tried to call it back and got a busy signal

This number called my business cell. It did not leave a message. I called back several times thinking it was a customer, but only got a busy signal. I think it is a computer randomly testing for viable numbers to sell. Or some other scam.