It happens that even relatives quarrel for a long time, let alone relationships with friends. If, nevertheless, this happened, and you understand that it was you who were wrong, that the person was seriously offended by you, and you do not want to lose him at all, then gather your strength and ask for forgiveness. This will cleanse your soul of the burden of the mistake you made and show your friend that you sincerely regret what happened. But how to ask your friend for forgiveness if she doesn't contact you and doesn't want to meet and talk? Try to apologize in writing.
This way of apologizing and asking for forgiveness will make it easier for you to admit your mistake, because it is much more difficult to do this by looking into the person's eyes and expecting to be pushed away at any moment. If you decide to write, then you should not use a computer, such intimate letters are written exclusively by hand.
Start your letter with a friendly greeting, and use a sincere, warm tone to convey your thoughts. Try to briefly and gently explain to the person what caused your behavior, words, feelings and actions at the time of the quarrel. You should not be too zealous to make excuses and defend yourself, for this your addressee may see not remorse and regret, but a desire to justify their action by the circumstances and confidence in their innocence.
Talk less about what has already happened, and more about how you can find mutual understanding and forge future relationships. You must remember that the insult that you caused your friend has not yet passed and it takes time for the passions to subside. Your sincere change letter can shorten this time and provide an opportunity for reconciliation.
After the letter is written, re-read it again, trying to evaluate its content through the eyes of the person whom you offended, analyze the emotions that each phrase can cause. Who, if not you, know your girlfriend, so cross out those words that could hurt her again or be misinterpreted.
Even if you don't get an immediate response to your letter, the important thing is that you showed your friend your remorse and regret and took the first step towards reconciliation.