Try to line up points in the binding! I know this will take many extra minutes of your time, but I've never seen it done before and could add an additional depth to your quilt! See what I mean...
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I would certainly ask for a refund or discount. The one who made the mistake should have a consequence for it or it shows the mistake didn't matter that much. Dismissing the mistake as it's okay gives support to the Whatever mentality that many have when they mess up.

Could you add another border and take it back to her and have her quilt it and not cut it? It sounds hard but you can do it. Just a small boarder would work.