I've been back and forth with Optus pretty much since january. Trying intially to work out a payment plan for bills I didn't get cen know I had.
The payment plan was halted by me when 900 dollars of mine couldn't be accounted for .
No option to restart the plan
And my shop which is suppose to have all the benefits of the Optus loop setup has not had a working phone for around 8 weeks.
No dedicated support, no one's found my 900 dollars, and only today after having loop for 8 months did I teach myself how to login to and setup the app.
TIO is only interested in if the contract has been properly observed. It sounds like it has and if you halted a payment plan then usually that then just reverts to you again owing the full amount immediately. Its good you are educating yourself on the tools etc involved as you have some responsibility to be able to use them. If $900 of yours has gone missing then you need to work out where it has gone yourself. Do you have confirmation of transfers from your bank account to Optus? Reciepts? When you have this information you can contact the billing department and ask them to chase it up.