Just on the basis of his blocking you alone, for sure, I don't think there's anything for you to do when it comes to him right now but figure that unless he changes his mind and contacts you, you'll just need to accept that you can't get any kind of resolution or anything else from or with him right now.
I'm so sorry that you're feeling the way you are. But something I'd like to say is that unless I misunderstand something here, you're the one who has an illness right now (two, it appears). You're the one having the absolute hardest news, of anyone in this situation, to process and start to learn to manage and live with. You're the one who likely feels the most scared and the most isolated. You didn't make yourself sick, and you getting sick wasn't something you did to your partner on purpose or to hurt him. Getting sick was something that simply happened, and the primary person in this it happened to was you.
I hear you making this about you doing something to your partner. It sounds like they were suggesting that, but that doesn't make them right, you know? I can't speak for this person, but by all means, even generally kind people have been known to freak out and say shitty things when it comes to a partner acquiring HIV or other kinds of illness. Point is, what he said may even be literally, completely wrong and just a bad reaction, not something you should assume at all to be true.
Unless I'm misunderstanding/missing something here -- like your partner acquiring HIV from you because of you knowingly not telling the truth to them, or something else that WOULD be about you actively doing them harm -- why do YOU think this is about something you did to them, when it's something happening to you?
Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only thing that ever has. - Margaret Mead