Ok, it’s not really a scam but an opportunity to get something you like from Optus. This is regarding the AlwaysWin promotion that they have been running for a while for prepaid mobiles.
Recently they have been awarding bonus prizes. So you will get 2 texts which have unique codes. The first unique code is the “real prize”. You will notice the second unique code is a bit of a waste of time. Often you may end up with the prize of a free ring tone.
If you don’t like it, then when it asks you for your mobile type -> select: “Unsure”, and then “I have never used Optus Zoo”. It will automatically disregard the ring tone, and give you a more useful prize (like talk or text credit).
This is something I stumbled upon when I didn’t know my parent’s mobile model.