Can you please share what CS suggested and how it was resolved? It might help other sellers in your situation.
They might have said to work it out with the buyer.
I found she got lots of awesome reviews. Among 287, it is quite natural getting a few negative reviews.
I don’t thing she should refund after completing such a massive work.
If there mistakes, buyer have rights to request revisions until they get the perfect work.
So, contacting CS was a great decision.