Missed a call then Called the number, just had music, no voicemail etc.

I called back number (03) 9081 1810 reached voice mail for a company called Secure Australia.

no answe

I get calls from this number regularly and when I answer there is no response and the call terminates. When I call back I get put on hold and then a recorded voice says I have called Secure Australia and my call is important to them and they will get me back to me ASAP and the call terminates. They do not ask for a return number.

Answer and they just hang up

called the number . just heard music. no one answered.