Whether it was rude of him not to answer is pretty irrelevant. Practitioners don't have to maintain contact with anyone they have terminated, and some I know regard answering communication from former clients as reopening a relationship, and it seems he did not want to do that.

So even if he was rude, it's not something you can change. He made a decision, and he had the right to do that.

What do you need to give yourself to let go?