Karma means: for every action, is a reaction...
When someone "wrongs" you, leave it to God/dess to avenge you, for those who wrong you, bring upon themselves the ire and wrath of their actions back upon themselves, a trillion fold! For it is said:
“How people treat you is their karma; how you react is yours.” Dr. Wayne Dyer
Why "sully" (soil, tarnish, degrade, etc.) yourself with more karma, by taking revenge yourself, for "you will bring about more nastiness and ugliness into your life"! By giving it over to God/dess (or whatever the aspect is that does such things~?!…), "it will be done for you", in a far more; creative, effective, nastier than you could ever; conceive, desire, imagine and/ or would ever think of doing to another person! Plus, it will continue to pay that person back, up and until they realize, what they experienced to begin with, they brought unto themselves, simply because their learned lack (“ego” aspect) is the reason for the lack they experienced in the first place! (learned; E-mptiness, G-rowing, O-ffensively)
“Beloved, never avenge yourselves, but leave it to the wrath of God, for it is written, “Vengeance is mine, I will repay, says the Lord.” Roman’s 12:19
Instead, go forth knowing that you are the child of the Universe, and that which is taken from you, will be recompensed (compensated, or given back to you) greater than you ever imagined! Venture in abundant peace, and it will be with you, for peace is our true Being. (Ego creates never ending drama and pain, simply because that is what was taught to us!) Instead, open and Be that which you originally and already are (prior to adopting and accepting "ego" as being real), then you are free! Just Be...
There's a saying, "When life gives you lemons, make lemonade".