We are currently in the USA - San Francisco, and cannot send txt messages. When we arrived it said we were entitled to roaming for $5 a day. This works and we can receive txt and have data, but we cannot send txts. I am on a samsung S9 and my wife a apple iphone 6. We have used the $5 a day service whist in oz and europe with no issues - but for some reason it does not work here. DO we need to change anything on our phone?
Make sure the numbers you're sending to are in full international format
So for example +6421xxxxxx
If you have a contact saved as 021 change this - even if you try to manually set +64 creating a message to a contact you already have saved as 021 the phone will recoginse the contact and revert back to trying to send 021.
Lastely make sure the message/service centre number is correct. You can google how to check this. VFNZ message centre number is +6421600600.