I too got this call, the +1 in front means it was an international call. There is a scan where they want you to call back and then they hit you with some outrageous charge. Most people now have this covered in there cell plans, but other can get a nasty surprise when the bill comes in. Don't call a number back if it has that +1.

Unknown number. Did not answer.

Just received a call from this number 20 minutes ago.  I was outside and didn't pick up.  No message was left.
When I tried calling back it says the number is disconnected.  i buy from Craigslist that's probably how they got my number.

Yeah, got a call (didn't answer) with no voicemail from this number. Same as above.

It was a call about loan forgiveness, but it was spam