Is it possible to delete 1star comment?

Hello, A customer bought a product from my store 4 months ago, he was very happy and satisfied, gave me 5stars and even ordered the second one last month. However, he mistakenly used alcohol while cleaning the first product (delivered 4 months ago and 5stars given) and the damage occurred. He contacted with me demanding refund. I said “I cannot help with refund since the product delivered in perfect condition. However, I want my customers satisfied with my service so I can give you 50% discount” He didnt reply and opened a case demanding refund (purchase protection). Etsy escalated the case and rejected since the product delivered perfectly. I tried to communicate again but he never replied and yesterday, he gave 1 stars to the second product (which is in perfect condition) with a comment “the customer service is very bad, not caring the customer etc.” I don’t think this is fair and the since etsy escalated the case, is it possible to open a case to demand deleting the comment?