Here's a scenario: You were getting those annoying robo calls from telemarketers so you signed up for the Do Not Call registry.
Now, you've gotten a letter from the "FTC" saying your Do Not Call registration has expired so you need to register again. That's wrong. The Do Not Call registry never expires.
You may still get calls from charities, political groups, or debt collectors. But it never expires when it comes to telemarketers. Once you add your number, for free, it stays on the list.