Happened to come across this last night. If you live chat with a sales representative they will be able to apply the bonus 5gb data.
Including my current plan and added bonus data, I'm now sitting at a nice 31GB/mth paying only $10!
"Bonus Data – Just to say Thanks"
We are giving you an additional 5GB of data, every month for no added cost – until you sign up to a new mobile plan. The offer will be added within the next few days and you don’t have to do anything.
There are no charges involved, we just want to thank you for being a loyal customer. You may still have some questions which may be answered below.
Q. Does the 5GB Bonus data allowance cost anything? Is there a catch?
A. No. We are giving you the 5GB allowance for free every month to thank you for being a loyal customer and to demonstrate that we value you as a customer.
Q. How do I know when the 5GB Bonus data has been applied?
A. You will receive an SMS to advise you of your new monthly allowance once that the bonus data has been successfully added on to your account.
Q. Will the 5GB Bonus data show in My Account or 24x7?
A. Yes. The 5GB Bonus Data will be reflected in your monthly total data allowance in the My Account & 24x7.
Q. Will it show on my bill?
A. The 5GB Bonus data will appear on the bill as Bonus Data Allowance – 5GB.
Q. Can I share the 5GB Bonus data allowance with other services on my account?
A. Yes. If you are on a plan that enables your data to be shared between devices, the 5GB allowance will contribute to the total bucket of data that can be shared across eligible services on your account.
Q. How long does the 5GB Bonus data allowance stay on my service?
A. You will receive 5GB Bonus data every month to use in that month, unless you decide to do any of the following:
move to a Data Share SIM
move to a pre-paid service
move to a new plan, or
disconnect your service.
Any unused data allowance expires at the end of each billing month.
Q. What if I exceed my included plan allowance as well as the bonus 5GB? What charges apply?
A. If you use your plan allowance plus the bonus 5GB in a month, extra data will be automatically added in 1GB blocks for $10 to use in that month.
Q. Can the Bonus 5GB Bonus data allowance be used outside of Australia?
A. No, your plan allowance and the bonus 5GB data is only for use in Australia.
Mod: As per comments, deal is targeted/invitation only. See here and other comments for more details and other user experiences. You will need to initiate live chat to ask if you are eligible.
EDIT 26/2- The webpage is no longer active. Here are screenshots of the actual page.
1. Part 1
2. Part 2
3. Part 3
Seems like everyone from OzBargain is on Telstra Chat, no available human agents :(