I have a question!

I received two calls today from a number starting with 010, so I tried calling back about four times. Twice, I heard an automated message saying the person was on another call and couldn't take mine, and the other two times, it seemed like they weren't picking up at all. When I checked a spam service, it showed it was a prepaid phone, and while there didn't seem to be any history of suspected voice phishing, it did show that about 10 people have searched for this number over the past year (though none in the last month).
What on earth could this be?