Keeps calling scammer

This number and similar numbers (end digit different) have been constantly calling late in the evening - 8pm late. Extension 5716 called 2x the evening before and out of curiosity I answered it to hear a woman laughing on the end of the call. When asked what was funny she hung up on me. The following night, this number called and the woman identified herself as calling from ? International, undertaking a survey on socialism and other things. Didn't undertake the survey, seems very scam like with requests for intrusive information.