1 Thessalonians 5:15
Make sure that nobody pays back wrong for wrong, but always try to be kind to each other and to everyone else.
Revenge never solves the original problem. It only intensifies your anger and never allows proper healing. Although it may be hard to do, it really is worth your peace to just let some things go! Whatever favor they never completed, let it go! Whatever they haven't returned to you, let it go! And for the sake of sleeping at peace through the night, if they never return, let them go! Get your peace back and let that "thing" GO!