dodgy dealings

I recently bought a car with a current roadworthy certificate.
but now not three weeks later I've had to shell out over 500 dollars to fix an oil leak and a hole in the muffler.
So in the spirit of my year of complaining I rang Qld transport and the inspectors office who deal with this type of shonky RWC.
They said
as I didn't keep the muffler they have no evidence. Never mind I paid the bill for it to be fixed.
They said
It cannot be proved I actually had an oil leak. So what did I just pay over 400 dollars for?
They explained
If I did want to take the issue further they would take my car and go over it with a fine toothed comb and any tiny little thing wrong and they would slap a defect notice on it and I would have to have it fixed in 14 days then back on the hoist for another going over. Then they might say it was all a bit inconclusive.
They admitted
that the whole RWC thing is a bit of a lerk. They get complaints ALL THE TIME but it is a mine field to act on them.
so their advice
is to just go about your business citizen and oh by the way
have a nice day.
Thanks.