You should be treated like a trustworthy human being! Remember that you are not chating/ talking to Boost, when you contact the call centre. Telstra run the lot for Boost (Philipines; poorly trained with bad systems structures). Telstra's call centre is the most complained about Company to the ACCC !
So, to get real action, I suggest you phone Boost Head Office in Sydney. Yes, you can do this (Mon To Fri only). I have on 4 occasions over the years and got good outcomes from Australian Team Leaders. As this is obviously a Serious 'System software malfunction" that needs fixing; as well as your personal refund, they should give you direct help. [Do not let them pass you on to the call centre as: "you were not helped before and Boost still have a billing software malfunction"!].
When you call, ask for the Team Leaderthat handles "Billing software system failures and that your case will effect many others"! The person that answers may(?) have to get back to you or pass on to another 'specialist' at Head Office. Make sure that you get the name of the person you speak to for any call back/ chase up. [I only had to chase them on 1 occasion; they are usualy good - within 2 business days].
So, if you want a refund and speak to a sane person, call Boost Head Office on: -
02 9299 9655 ( last number I used). When you get through, do not press 1, or you land up with the overseas call centre! Press 2 for the Head Office Team. Not sure if their 1800 026 678 gets to Head office still, or sends to Telstra's call centre again ( can't test it till H. O. opens on Monday - business Hours).
Good luck; would be good to hear how you go - for others' needs in future!