Sometimes organisations restructure their plans after they've paid for ads to go out. And sometimes it's just recruitment agents looking for CVs they can put to their clients when real jobs do come up.
I sympathise. I went for an interview a few weeks ago. Didn't get it - fair and square. I then got an email saying the post had been withdrawn anyway . Why would I need to know that a job I didn't get didn't exist anymore???
YANBU. I have had interviews for jobs which ceased to exist afterwards. It could be that I am just crap and that is what they tell me, but whatever, I put myself out to be somewhere. If it is truly that I am unsuitable for some reason I would rather they told me why so I could try to do something about it.