The "One Ring" or 'Wangiri" scam usually happens in the overnight hours, may repeat several times in a row, and may include a voice-message saying it's urgent you call them back. DON'T!!!
If you call the number back, it works like a 1-900 number, turning into toll charge... for YOU!
Here is what you can do to avoid the "One Ring" or "Wangiri" phone scam:
a. DON'T return the call
b. If you don't make outgoing international calls, ask your phone service provider to BLOCK outgoing international calls, helping stop you (or someone you know) from accidentally calling the number back.
c. If you receive one of these calls, DON'T answer or return the call, and report it to the FTC (Federal Trade Commission) - HERE.
In addition, if you're tired of unwanted domestic solicitors calling you, register your phone number with the Federal Trade Commission to help stop it - HERE. I registered in 2008, and it has helped significantly.
Allow these scammers to learn the value of self-worth, by getting a 'real' job.