Caller ID is "(617) 826 1016" (the default format on my system). They left no message.
I call after hours (using *67 to block my number). The message is "Thanks for calling. The survey you were called for has now finished. If you would like to be removed from our list for future calls, please, press 9." I do not press 9 as this can make things worse.
Let me contrast this to a real survey from Gallup. Gallup puts their name in the caller ID; these guys don't. Gallup's message identifies themselves and indicates that you can't call to take the survey this way; these guys don't. Combining everything makes me think it is a SCAM. Likely a scam phishing for info under the guise of a survey.