It's the survey scam. Call back gets, "Thanks for calling, the survey you were called for is now finished..." Even if you call back within a second of their call, this is the message you get." The scam goes like this, you get a free something for answering a few questions. Some people report that the so-called free gift is a wal mart card for 100 dollars, some say they were offered free Disney tickets, etc. After you answer the questions you'll be asked for a credit card number to process the small handling fee. There ya go. Not free if they need your credit card. Block it.