Hacking into my e-mail account?

A moderator in one of the yahoo groups I was in hacked into my account. It is definitely him because he deleted all of his messages. It happened a couple of weeks ago at least. His messages might have been a bit embarring - he confessed to breaking and entering into a girl's apartment, although I didn't think it was so bad because it happened so many years ago. I'm thinking that I should just forget about it, but I have been writing to him and he won't write back, and I feel quite upset that he won't apologise or write back at least......he did the wrong thing! I wish internet security wasn't so poor so I could get him caught out.......he is extremely smart so he would have covered his ***. So, should I just forget about this? I can't change my e-mail account pword because it won't accept the school I went to. What do I do? I feel quite hurt. I want to tell everybody on the groups he moderates. I just feel so angry, but is that really immature? Tell me what you think!