It's got worse instead of better!
I might have known that expecting even minimal competence from Optus was too much to expect. The SIM card that was supposed to be couriered to me did not arrive and the old card is still active with a credit balance of only 20 cents!
And, to cap that, I finally got a call in answer to my letters -- from a girl who was totally unaware of what Scott of the internet enquiries branch had done! I told her to talk to Scott, get her story straight and ring me back but what will transpire from that remains to be seen.
So, only weeks after acquiring it, I have at the moment a totally unusable Optus cellphone! Unbelievable.