I called back number (08) 7999 9629 rang once then gets disconnected automatically.

I think its the Woman's and Children's Hospital Foundation, they're seeking donations.

I think it is a charity trying to get donations.

I have calls from (08) 7999 9629 and (08) 7200 3156. Not sure who they are as they don't leave a message and don't answer their phone. I have added this number to my auto-reject list and suggest you do the same. 7/10 times it is just a charity like MS or guide Dogs. 3/10 it is someone offering printer ink or SEO optimization.
What I can tell you is that this number is most likely from Alice Springs.

Keeps ringing but does not leave a message when not answered..