Only one who forgives shows how he really appreciates God's forgiveness. If we want God's forgiveness, will should forgive freely.

Try to forgive your friend. Not quite long ago I had issues with a friend too. Someone who I took as a brother and helped with several of problems, started insulting me and spreading false information about me. But meditating on the scriptures helped me developed the right disposition of the heart. Freely forgive, as God freely forgives repentant sinners.