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.
The FCC can issue warning citations and impose fines against companies violating or suspected of violating the do-not-call rules, but does not award individual damages. If you receive a telephone solicitation that you think violates any of these rules, you can file a complaint with the FCC. There is no charge for filing a complaint. You can file your complaint using an online complaint form. You can also file your complaint with the FCC’s Consumer Center by calling 1-888-CALL-FCC (1-888-225-5322) voice or 1-888-TELL-FCC (1-888-835-5322) TTY; faxing 1-866-418-0232; or writing to:
Federal Communications Commission
Consumer & Governmental Affairs Bureau
Consumer Inquiries & Complaints Division
445 12th Street, SW
Washington, DC 20554.