Hi extremely_annoy
Have you tested your line with out the T-hub phones connnected, ie regular phone so we know that you don't have any faults on the line.
If you have tried that, the fault might actually just be with the T-hub handsets, if that's the case I would ring our faults line or speak with them directly via live chat to organise warranty. Live chat can be found here : https://livechat.telstra.com/
- Jon