I have returned my TPG hardware in line with your instructions. It was delivered to your North Ryde address on 28/10/21. I have confirmed this with Startrack.
However I was charged a $192 Non-Return Fee on 11/11/21. I sent an email regarding this issue a week ago and haven't heard anything back.
I expect this charge to be refunded immediately. If it is not refunded to me I will be cancelling my NBN service.
I would strongly encourage anyone who has been unable to obtain a refund from TPG for the "non return fee" modem lodges a case with the Telecommunications Industry Ombudsman as there is no one within the TPG customer service team that will actually help you.