KNOXVILLE, Tenn. (WATE) – Crooks from overseas are buying or stealing lists of U.S. cell phone numbers and using computers to mass dial.

What the schemers do is call and hang up within one ring.

Rhonda from Morristown asks: “What happens if you call back? I’ve heard you could get a big bill.”

What many people will do after receiving one of these calls is call the number back without looking at the phone number.

That could cost you dearly if your return call happens to come from the islands of Antigua, Grenada or Jamaica where a lot of these one-ring phone scam calls have been originating.

“It’s an international call, and it’s to the Caribbean Islands usually. It’s a $19.95 charge,” explained Jerry Tipton with the Better Business Bureau. “You go to an adult site. Oftentimes they’ll put you on hold for a number of minutes and it’s $9 per minute, thereafter.”

The practice of third parties placing unauthorized charges on wireless accounts is called “cramming.”

The Federal Trade Commission receives thousands of cramming complaints every year, and they expect more.

Tipton has some tips on what to do if you fall for this scam.

“Notify your carrier immediately. Make note of the time, the exact time, and date. And tell them this is what happened. They will generally work with you and try to resolve that,” he said, adding that most of the time, the charges will be removed.

One final thing: if you don’t recognize the number, don’t answer it. If it’s a legitimate call, they’ll leave you a voice message.  Don’t answer if you don’t know where the call is coming from.

You can see Don Dare’s 6 On Your Side Answers every Tuesday and Thursday on 6 News at 4:00.

If you have a question you can send Don an email at ddare@wate.com or call his 6 On Your Side hotline at (865) 633-5974.