Haven't read every post, so sorry if this is a repeat... there are a couple of angles from our perspective.
First - Mobiles
Then - Qantas
In the past I have experimented with various techniques for managing international roaming costs, but these days we don't bother with local SIMs etc but use our mobiles as little as possible, and mostly use wifi.
For connectivity we just used (note past tense) PAYG charges as needed the occasional call for coordinating local accommodation, taxis etc and if someone from home called they would leave a voicemail, and I called them back via VOIP on wifi for next to nothing.
So in May we headed off to USA and Europe for 6 weeks thinking we had our usual phone service arrangements.
Arrived in US and wondered why phone was not roaming ... contacted Mynetfone support and informed, Oh yes we cancelled your PAYG roaming and if you want to connect you need to buy a "pack" and pay $10 for each day when you send 1 SMS, or make 1 call, or receive a call. And you get 200MB of data.
Reason ? too many of their customers were having "bill shock" from data roaming.
Apart from the annoyance of the commercial proposition, the fact they cancelled the roaming service without informing me I found shocking.
OK, fair reason to have the "pack" as a commercial offering, but why penalise customers like us who don't use mobile data roaming, and actually understand the system. I have been roaming on international trips ever since GSM made it possible and never had "bill shock".
Our previous trip over a month in Europe and our total roaming charges were around $15, so ....
No Thanks !
Anyway, we muddled through 6 weeks with just wifi / VOIP / emails etc. There were a couple of occasions where I really would have liked mobile voice connectivity and would probably have spent $10-20 quite happily. Never mind as I have switched phone providers to one where they still have PAYG at acceptable rates.
So, Qantas...
That Qantas money website ONLY works via SMS authentication is hopeless.
Due to the issue above we could not receive an SMS, and found it impossible to access my wife's account even though we had perfectly good wifi internet access.
I have recollection (but not sure) that it previously also worked with an email verification, but maybe I am confusing with the QFF site.
While in NYC we tried calling the QF money support line simply to find out how much was owing for the payment we knew would be due.
As a separate issue, we were continually disconnected when trying to get through the menu - I suspect there may have been an incompatibility between the phone tones from the phone we were using and the QF IVR receivers.
The only good thing ...
Using the Qantas Money app on your phone, you don't need the SMS as for some reason they accept the access from your phone with the passcode.
I had the app on my phone and could access my account, but we could not access my wife's credit card account as she did not have the app on a separate device.
The moral of story ...
Instal the app.