It's called 'caller id spoofing'. The people calling you can make any phone number show up on your caller id. They're making a number show up that charges you money if you call it and press a certain key.
At the same time they've disguised the messages on their pay by phone system as surveys. Those messages normally tell you what you're buying and how much it costs.
Check your bill for unwanted charges if you called this number back.
called the number back and got "you were called to participate in a survery but the survey period has expired" I didn't even call back from the same number...interesting?
Auto-message that said it was "Ann from Political Surveys of America" and if you took a short 30 second survey you'd get two tickets to a cruise to the Bahamas. Riiight. You had to press 1 if you wanted to do it. The message repeated itself once more before automatically hanging up.