One-ring robocalls trick you into unknowingly making international toll calls, which can add hundreds of dollars of charges to your account. One-ring scammers use automated dialers to randomly call hundreds of numbers, but the calls are disconnected after one ring. Victims see a missed call in their call log and, thinking it may be important, attempt to call the number back. The number appears as a typical U.S. 10-digit number, but in reality, these are international long-distance calls, often originating from the Caribbean.