Hope you are doing fine!
Amazon doesn’t give you direct customer contact number if you opt for FBA. But Amazon provides you encrypted email id in order detailed page. You can write a mail to this customer and ask them to remove that comment.
Also, you can tell him that you will make sure to provide better quality products next time.
I’m going to go ahead and open our conversation on my end for now, If you run into any other issues at all, feel free to reach out to me, I’d be more than happy to help!
Have a great day ?