Assuming scam. I missed a call from this number on my business mobile, upon trying to call back, I get the message from optus saying this number is disconnected. Had a dodgy call a few days ago from a similar number so guessing it is a scam as well.

Left a *recorded* message saying "called you many times but no answer, for details press 1 for english and 2 for chinese' followed by a chinese recorded message saying my visa has expired. Clearly a scam.