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.
Well the "free cruise" scammers have a new phone number and their dialing software is having a very busy day!
What you need to know:
(1) This is not a telemarketer
(2) This is not a bill collector
(3) This is not really a survey, although they claim to be one
(4) This is a SCAM and it is designed to part you from your hard earned money
(5) The cruise is NOT free
This scam has been around forever. The phone number keeps changing (and by the way, they are using VOIP, so the apparent origin of the call is meaningless). They can be anywhere on the planet.
Answering may (or may not) increase the rate of future call attempts. However, I run a honeypot phone number which appears to be disconnected (it isn't), and they continue to hit this number on a regular basis, so mostly they seem to be blindly dialing numbers.
If these sorts of calls get on your nerves, I suggest using Google Voice, or a VOIP provider with call treatment features. Call blocking phones such as the Panasonic will not help much against a scammer who changes phone numbers every day or two.
Sort of makes you long for the pre-VOIP days, doesn't it?