Hello Thomas Anglin,
You mention the review is not inappropriate; so, I would contact the client to keep open communication and positive results for all involved.
Have you thought about doing any of these ideas on IDEA?
You could also comment to the review.
I would look at this as a learning experience to better my services for the clients; no worries.
I also do not see any reviews on your page, anyway.
I hope you feel better about this.