Circumstances made me insult a person few years back. I realised my mistake a year later. Since then I asked forgiveness from that person a number of times but no reply from his end. I believe I have got enough punishment for that insult, and till date I am suffering. How do I get freedom from this guilt?
Your question is a very sincere and it sounds like you have done everything you can to make amends. Give the incident to God now and He can purify the mistake. When the mistake comes to mind consciously hold that thought up to the Light and in the language of your heart ask God to hold it for you. That should help to ease all the quilt too. Yogananda had a very close friend that was angry at him for many years and, as the story goes, Yogananda kept blessing this estranged friend and never did reconcile the problem. But Yogananda sent the friend mangoes every Christmas anyway, in blessing to the friend. You don’t need to do anything outward, just inwardly, now, and be sure to forgive yourself, also. Many Blessings on your efforts.