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 My cell. Transcript from google voice (you get the jest, some words not translated quite right):
Hello, this is ann from political opinions of America you've been kathalee selected to participate in a short 30 second research survey pertaining to our nation's debt crisis. And for participating You Will Receive 4 8 2 day cruise for 2 people to the Bahamas, courtesy of one of our supporters for 2 days in a small port tax will apply. To begin the survey. Please Press 1 now 2 decline the survey and be removed from our list. Press 9 Thank you. Hello, this is ann from political opinions of America you've been kathalee selected to participate in a short 30 second research survey pertaining to our nation's debt crisis. And for participating you won't receive 4 8 2 day cruise for 2 people to the Bahamas, courtesy of one of our supporters great to Moody's at a small port tax will apply. To begin the survey. Please Press 1 now 2 declined the survey and be removed from our list. Press 9 Thank you.