Is it not an offence to advertise services or fares without an AOC? I'm sure Torres could quote the applicable CAR!
A search of the CASA site reveals only one operator with the word "mountain", and that is a legit company in Tassie. Mountain Aviation show a Helio Courier as part of their fleet. There is only one Helio Courier currently showing on the CASA register (although I actually thought there were a couple around), and it is registered in NSW.
Mysterious indeed.