I believe karma exists, but it’s decided by each person for themselves. If you have guilt about something, you’ll find a way to punish yourself or surround yourself with people who will. If you’re a narcissist and/or are too stupid to have guilt, you will seem to get off with no repercussions. In the end though, the people with no guilt, also can’t feel. Life tastes pretty bland, so that’s a punishment in itself.

TL/DR: Make peace with person/people/yourself on things you feel guilt about.