I got the same thing tonight. I put the call back number in a reverse lookup and discovered it was an unlisted land line number in Arlington, VA. I made an online report to the Arlinton County Police Dept. because someone on another web site said they called back and the person asked for their card number--obviousely a scam! Hope they catch the person!
Received a call like the others. This purported to be from the Loudoun County (VA) library (strange!). Said card starting with "4429" was on temporary hold. When you call, you get a recording (with no identification) asking you to leave a message.