I sent a message to my boyfriend apologizing for what I did wrong, but he didn't add my friend and didn't call me back. I told him a lot, but there was still no news.

If you can't let go, you can find him, apologize to him in person and talk about your opinion. If he can accept your apology, you should pay more and slowly restore his heart. If he still doesn't forgive you, then you'd better let go of this relationship. What you did was really unacceptable and unforgivable to him, which showed that he was really heartbroken by you and gave up. You should relax, too. Since you don't love him, don't nag and pester him, which will only make him look down on you more, let go of the present, continue to go your own way and learn from your mistakes.