Frankly, if you cannot receive Communion, it means that you are in a state of mortal sin. You should get out of that state as soon as possible by going to confession and correcting the situation. If you die in a state of mortal sin, you go to hell. So yes, you SHOULD always try to correct the situation…unless you want to toast for eternity (and trust the saints who have seen Hell…you don’t).
I don’t exactly understand how a Catholic would be banned from Communion if it is not their fault…an example of what you are thinking of would be helpful.
I assume that you may be referring to divorced people who have ‘remarried’? News Flash: if your first marriage was in the Catholic Church, you divorced but did not/could not annul the marriage, and civilly married someone else…in the eyes of God you are not married. You are cohabiting. You are committing adultery. In my opinion, the only thing to do is to leave the second partner asap, go to confession, and start receiving Communion again.