How much money are we talking about here? What kind of business?

Invite her in to the store, give her a display area with a sign “Designs By Not Me” or some hippy version, and take the small financial hit in the moment, but enhance your entire business model in the long run. You get experience handling consignments, you improve your legitimacy as a community member, learn what sells and why, and step up your own game a little. Also, this gives you the best way to control the aesthetics of the presentation.

Play this right, it’s a win-win-win with a 3-way tie for first between you, your friend, and your customers.

Just respond to the review with positivity, empathy, and honesty. Do not address her condition directly, simply say that there was an unfortunate misunderstanding after the job was completed, and you are reasonably certain that the issue was not anything that had been addressed by the former contract, and you wish her the best, and you welcome any opportunity to work with her to make her happy, etc etc. Be kind, be positive, make it somewhat interesting to read.

As a prospective client, I always read the business responses. They really show the character of a business.