I too looked up the number and found here that it was Connections Academy. I answered, "Hello," and when I did not receive a response two or three seconds later, I hung up. If it's important, they'll call back and actually speak this time....
We withdrew our son from Connections Academy and they were calling to pick up the materials we needed to return. When I answered, there was no one there, but I called back.
Connections Academy, an online charter school. They were calling to let us know when to send back our school materials and let us know the labels had shipped. It was really creepy though when I answered and all it said was hello and then had dead air.