Insist to them that you want roaming barred in the HSS. Say that (HSS) specifically.

I asked a similar question a few weeks ago , if I set my spend limit to $0 Is that enough to stop it triggering a charge?

Their answer below

The most reliable way to make sure you are not charged any roaming fees is to either remove your SIM card from the device and keep it somewhere safe until you are back in New Zealand, or set your spend limit to $0 and bar roaming. You can do both through the 2degrees NZ app or your My 2degrees online account.

Brunzy:

 

I asked a similar question a few weeks ago , if I set my spend limit to $0 Is that enough to stop it triggering a charge?

 

Their answer below

 

 

 

The most reliable way to make sure you are not charged any roaming fees is to either remove your SIM card from the device and keep it somewhere safe until you are back in New Zealand, or set your spend limit to $0 and bar roaming. You can do both through the 2degrees NZ app or your My 2degrees online account.

 

Yes that would work too, but might trip you up later if you need to buy a pack or make an international phone call. Not that it can't be undone at any time, just could be a minor annoyance.