Mokka 1.7 Start/Stop System

Hello, have a brand new Opel Mokka with Start/Stop system. With us are 2 to 5°C outside temperatures and I drove a longer distance (60km): the Start/Stop system did not work. I talked to the service dealer of Opel and got the answer that at these outside temperatures (this is near freezing point) the system would not work. Does this correspond to the experiences of the Mokka drivers? From which outside temperatures would a defect be detectable then???? Bin et what unsettled. thank you and greetings Huby