I'm not really sure. Perhaps contact a breeder for advice or your vet. Your dog may just not like the whole thing. Being a mama may not be in her destiny. Are you paying for the stud service? Have you talked to any of those owners as they may have some insight.
Well my answer may be disappointing but it is sometimes the case that not all dogs "do what comes naturally" with abandon.
I have known some people whose female dogs did not like sex...and there was nothing they could do about it.
It might be that she was a bit shocked, if it was her first time? She might grow into the idea?
I presume the male dog was the appropriate size for her? (well, that's most likely a "yes" if you have an Aussie stud male.)
Another consideration is -dogs are like us inasmuch as they have to feel a chemistry with the mate. It isn't just a mechanical act. I wonder if the two dogs spent more time together -that might help?
Dogs certainly do have their preferences when it comes to sexual chemistry.
Sorry to say it really doesn't appear you are very knowledgable in regards to breeding and neither is the owner of the stud. Breeding animals is a science, done correctly, and a big responsilpnility, not only for your female but the pups. The fact that two dogs are registered really means little. You need to be looking at breed standards, hereditary health issues, temperament, etc. Aside from all that, how old is your female? Females can differ as to when they will accept a male for breeding. Yes, they should "tie" for a period of time. They should not be left unsupervised at any time or you have no idea if/when they might have bred. I strongly suggest, assuming you have no experienced mentor, do do a lot of reading about breeding, possible complications, whelping, possible C sections, care of newborn pups, possible complications, worming, vaccinations, Cocci, Parvo and the list goes on.