I think she's seeing mixed signals. You say that you want her out of your life, yet you haven't blocked her on social media (unfollowing her isn't sufficient) and haven't blocked her messages and calls (there's an app for that)
Also, I would guess that she believes she has the right to be endlessly forgiven....Or perhaps doesn't see that she's done anything wrong at all.
I'm wondering if her parents ever said "no" to her as a child or had her suffer consequences for her behaviour.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.