Fuel card mob - sign up and get 1c a ltr off bowser price

I called back number (03) 8842 3714 spoke to a woman who said company name is Fleet Card.

This number rang twice in 5 minutes and the calls went to message bank. Listened to the recorded message and could hear it was a call centre as there were voices talking in the background, also I could hear the caller rustling around on their desk but both times they could not be bothered to leave a message. Must not be legitimate if they cannot be bothered leaving a message to identify themselves.