Alan stated it perfectly. It's an agent's prerogative whom they choose to work with (or not work with) and I'm sure he had his reasons. Could have been that he was just too busy to He could have given a better explanation, and if you're really upset over it you could send a letter or email to his broker.
At any rate, you're probably better off finding a realtor who WANTS to work with you and if your qualifications are legit and your wants and needs are realistic then you shouldn't have a problem finding one. After all, this agent did 2 months of legwork for free, so your new realtor is being delivered a buyer who is in better shape!
Best of luck and good riddance to that dude!
And as such, we're allowed to decide that we don't want to work with that buyer anymore. But professionalism and common courtesy says that you're owed more of an explanation than "radio silence", and a "good luck" email.
I'd say it sounds like you've dodged a bullet here, as it doesn't seen like your Realtor was very invested in assisting you.