Karma is inescapable. Your actions DO return to you. It may not be in this lifetime, but it certainly will return to you. How you deal with the return of this karmic energy determines whether or not you bring your soul further into balance or create more karmic energy that must be dealt with at a later date. If you seek to learn from the seeming injustices in your life, chances are that you will be balancing your karmic books rather than increasing your karmic debt.
For me, it was helpful to look at karma as a sort of credit card. Each time we do something in our lives motivated by love, we are "paying off" some of the karmic debt we have built up over our many lifetimes. Each time we act in selfish interest, we are charging something else to our credit card. The goal is not to have a credit due us, because in doing so, it would mean that someone, somewhere, still owed some debt. The goal is to get our balance to zero. To pay off our karmic credit card and make no more charges on it. Then we will have reached our goal and there will be no need to return to this physical plane and we will once again be reunited with the Divine.
Karma is often thought about as being some debt we are repaying from a past life. But karma can be "paid" in the same lifetime it is created. We can read in many sacred texts that what you sow is what you reap, what you give comes back to you three times over, as you do, so it shall be done to you. All of these are speaking of karma. Even Jesus spoke of karma when he said we should do unto others as we would have it done unto us since that is exactly what will happen.