After saying hello, Recorded message simply replies "goodbye" after a few seconds & hangs up.
Concerned this could be one of those scam companies that calls & if you pick up, they charge you somehow ... or they want you to call back so they can charge you

Could not understand caller except for the ok at the end of his message.  My phone is on the government DO-NOT-CALL list. told him so and he hung up.  Probable scam....

Didnt answer didnt recognize the number... no voice mail which means I'll never answer it now.

I keep receiving these calls  "Dir Assistant" from different area codes. I don't answer them. They don't leave message. I'm on the national do not call list.
Sample of the other phone numbers:
559-555-0141
504-555-0136
708-555-01555
713-555-0155
571-555-0142
440-555-0130

Same issue, no voicemail, calls from multiple "555" numbers throughout the day.  Additional numbers to add to the list above, I got some of those and these others:
347-555-0122
580-555-0143
774-555-0161