Let down by parents - what do you think about this situation?

Bro, that sucks but they probably aren't telling you everything. You know their monetary situation better than I do, and they know the latter better than you do. If they didn't give you a real reason, and deflected the question....they don't want to tell you the real reason. You probably don't know how much of their income is truly disposable. If they invested it, they invested it because it was in their best interest.

Also, they did accuse you to deflect blame (because no one wants to acknowledge their own BS), but truly explore yourself. Are you entitled? You say that you are hurt because you are not going to receive the money. It seems like you felt entitled to the money because it was promised to you. One may be deserving of things, but no one is entitled to anything.

You kind of just have to swallow your pride, and look at your next best options, independently. I can see why you would be hurt but you should learn from this. Don't get excited over promises of future-action, even from your parents. They are only human. They want to make themselves feel good by promising things. Most people flake promises, whether there's money involved or not.

I've gone through something like this before. My brother told me that he would give me 1000 to help me get veneers a few years ago, but he spent it on himself instead. He spend well over 25,000 on things that I felt were trivial. I was and am still a little hurt because as time passes my front teeth become more sensitive, and I'll never get as good of a deal as I had back then. I never brought it up because...I was never entitled to it. It would have really helped me but that doesn't entitle me to his money.