It started with a 30-second phone call, and ended after a three hour hard-sell for a $NZ4500 ($4227) vacuum for a New Zealand family.

Mother-of-three Leonie Padgett, from Dunedin, said the sales pitch was "the worst experience", but South Island Clean Air (SICA), which relocated from Auckland to Dunedin earlier this year, stood by its product and sales' technique.

Padgett said three days after she was cold-called by a person wanting to do a "quick" survey, she was contacted by a SICA employee saying she was the daily winner of a prize.