Some people in the Christian community confuse the term repentance with apology. An apology can show regret, and a true filling that one is made a mistake that they should have not have made. But salvation requires more than an apology, it requires repentance. Repentance is a changing of one's heart, a changing one's lifestyle.
If a child continually tracks mud onto the carpet and when called by the mother to cease that behavior, and the child continues to apologize but never changes their behavior, is that apology valid? At some point either the behavior has to change or the mother must administer an appropriate punishment. And so it is with our transgressions against our Creator.