The failure case that matters for excess data is not the charge, it is the charge you cannot pay. Providers do not send you to debt collection over a prepaid balance. They stop the service.
What the TPG terms state
The summary is direct: if there are not enough funds in your prepaid balance to pay for excess data, your service becomes inactive until you top up. There is no negative balance carried forward and no fee for the state itself. Your data and calls stop, and they restart when the balance covers the charge.
What inactive does not mean
- It does not mean the number is gone. Keeping the number requires keeping the service recharged or transferring it.
- It does not mean a penalty. There is no late fee published for insufficient balance.
- It does not reset. The excess already incurred is still owed and the service stays inactive until it is covered.
So the practical sequence matters: top up enough to clear the excess, not just enough to reactivate, or the service comes back inactive again. Providers differ on whether a top up auto-settles the arrears, and that detail is not published in this summary, so check it in your account rather than assuming.
The prevention is boring and effective
Auto recharge is the direct answer where a provider offers it. The Boost terms make Auto Recharge available to customers who have registered a valid credit or debit card, and set a data limit alert as a second layer. Two mechanisms, both published, and neither requires you to remember anything.
What we could not verify. Where a provider has not published a figure we mark it unknown rather than estimate it. Re-read the provider page linked below on the day you decide.