Mine rang once also - however, I read about a scam where people hit call back and it goes to an offshore account that then bills you hundreds of dollars for "services". Basic rule, if was important, the would leave a message.
Just called at 1013 am. It rang once then hung up. I Googled the number. I blocked the number. I never answer calls with an unfamiliar number. EVER!!
If it's an emergency, they know the routine.
You can't be too careful people. Create a code for family members. It works!!
Rang once, hung up before I could answer it. I guess it's just a scam to get you to become curious and call them back. My cell number is on the national Do Not Call List, so they shouldn't be calling me at all.