Hi Amanda,
All working now. Thanks!
Sharing a further update as to the solving of this mystery, in case it assists other people. An extremely helpful person on MYOB phone support suggested that I check the "spam" folder of my iPhone SMS messages (which I didn't even know existed). I found this by clicking the menu in the top left-hand corner of the SMS messages page.
Sure enough, there were about 50 authorisation codes that I have tried to send over the past 2 months.
There is then the option to mark as "not spam" and the codes are now received in the usual way.
After many requests for assistance from MYOB, including hours long wait times to speak to anyone, and MYOB repeatedly closing my case before it was resolved. YOU have solved the mystery.
Thank you. Like you, I had no idea there was a SPAM folder. And there were all my codes.
:-)
