"boiler room" no conversation but could hear others in the background

Left message to call back at 5166921902. The voicemail reported the number as 8768794987, but Caller ID said it was 6466047791, so there's three different numbers associated with this call.

Same as above.

Asking for the medicare holder in the household. Told them there is no medicare holder and they acted surprised and i couldn't hear what they said afterward

Answered the phone call (called ID shows 646-604-7791).  Voice asked for me by name, I replied how can. I help, called terminated call by hanging up.