Clearly just wasting my time.

Don't bother answering.

called back,"extension ?????? not available leave message

I have had a few missed calls in the last few days from this number. I answered their call today and the lady (named Helena) said she was calling from Zero Research Centre and asked me questions in relation to my employment status. She knew my mobile number, email address and postcode but not my date of birth. Any details she didnt have I lied about. She said I would get an email from them soon to thank me for taking part in the research.

Dont bother answering the call. Just hang up, its easier :)

Scam research organisation. Just hang up when you see this number. Nuisance.

I called back number (03) 9912 7109 reached voice mail but did not say from what company.