I am currently with Tangerine 25/10 NBN.
After moving to my new house, I used their moving house link on 14th October. Everything went smoothly until I received a new bill. Tangerine bills on the 5th of each month, and I had already paid up to the 5th of November for my previous address. However, the latest bill is for the period from 14th October to 5th December at my new address. I contacted them via chat support, and they informed me that the previous connection was cancelled, so there would be no refund for that, and I would need to pay for the new connection starting from 14th October. As a result, I am being charged again from 14th October to 5th November.
Update
I was planning to file a complaint with the TIO, but the TIO website advised me to first submit a formal written complaint to the service provider. I sent an email detailing the situation, including information about the overlapping billing period and chat support records, asking them to reconsider the case. As a result, they agreed to waive the charges for the overlapping period.
Lodge a complaint with the TIO.