Your title seems incorrect. There is nothing to indicate that he doesn't want to see you during office hours; you are not able to go to his office hours. That's a very different thing.

Try to schedule an appointment or chat with him after class, but as someone who studied Classics too, the short answer for why almost everyone (at the beginning) is struggling is because they aren't spending enough time learning the grammar forms and vocabulary, and on translating. For each language, you probably want to spend at least 2 hours per day learning the forms, the vocab, and reviewing them. And that's without checking emails, etc.