One-star customer!?

Hey everyone, I could really use some advice! So, I recently got hit with a one-star review from a customer. I reached out right away to ask what went wrong, and they asked for a refund. Since I'm selling digital products, refunds aren’t something I offer, but I did offer them a free editing service, which usually costs extra. They replied, saying my no-return policy is poor and mentioned they’ve already completed the invitation with another vendor.

To my surprise, I found out that this customer is also a seller. As a new shop owner (my shop is just 4 months old), I know how much damage a one-star review can do. Has anyone else been in a similar situation? How did you handle it? I’d love to hear any tips on managing reviews, dealing with policy complaints, or just navigating this kind of situation. Thanks in advance!