Transport SA asleep at the wheel, and rude when awakened

On Monday I paid for a numberplate for my recently acquired car's bicycle rack. This, I expected, would enable me to comply with the law.

There was a problem, though. The Service SA customer service person with whom I dealt told me that I wouldn't be able to collect it (the quickest delivery option) until after Christmas, ie for at least 10 working days. I was planning to carry a bike on the carrier over the Christmas - New Year break, but now, it seems, I won't be able to do so.

I understand that the manufacture of number plates has been outsourced to one private firm in WA (Western Australia not West Africa I believe). Why this is so escapes me: vehicle number plate production isn't rocket science, and clearly the local market would benefit from a bit of competition.

Anyway, after mulling over the issue, I decided to contact Transport SA to see if I could use a temporary home made number plate to tide me over the gap. I rang the call centre (131 084) at noon today only to receive a recorded message stating that there were too many calls and that I should ring back later. Then the line hung up.

Can anyone advise me of how I might bring these matters (the excessive delay in producing the number plate and the automated rudeness) to the attention of someone who has the authority to do something about them ( and preferably, at least in the first situation, before Christmas)?