Sometimes, you hurt someone in a way that is dealbreaking. I think most people will probably do this at some point during the course of their life. Not to the same degree, and not with the same culpability, but it’s something that everyone is capable of doing.
If you do that, it’s important not to put pressure on the person you hurt to forgive you.
If they’ve asked you not to contact them, respect that. Even if you think that you understand what the problem was and you’ve now solved it. Even if you think you’re trustworthy now. Even if what you really want is a chance to apologize.
People you’ve hurt don’t owe you their attention, and they don’t owe it to you to help you learn to be a better person. They don’t owe you help getting atonement.
When you’re in a hole, stop digging. Don’t keep hurting the person with constant invasive attempts to apologize or fix things.
Sometimes you can’t make things right. Some things can’t be undone; some damage can’t be fixed.
What you can do is move on, and learn from the experience. You can learn what you did wrong, and figure out how to never do it again. And you can build a life in which you are good to others, while respecting that the person you hurt is no longer part of it.