The Do Not Call registry stops legitimate callers but it can't stop criminals who call from overseas using spoofed (therefore untraceable) numbers. If you are registered with the DNC, you can be assured that any nearly any unknown caller might be a scam and you should not answer the call and never call back. If no message is left, you might want to block the number.
Rather than an instant hang up upon voicemail, I heard what sounded like a call center in the background. Never answer a number you don't recognize, it's step 1 in the fraudster game! I get calls like this everyday but they seem to be able to scramble the numbers to appear differently.