Defamation of Goodwill

Hi I have started new business of apparels and am a registered seller on, Few days ago I got an order of a unstitched dress material which we have fulfilled as per amazon's procedure and the product was delivered to the customer, but we received a return request from the customer stating that the product quality is low and she found stains on it, I spoke to the customer and asked her to return the product and she agreed to it, however she has left the negative feedback on the website about our products, but when we receive our product there was no defect and it was completely fine, I spoke to the amazon seller help and they assured that they will remove the comment on the website, but instead of removing the comment they send a reply over the mail to me stating that they cant do anything about it and the comment will be completely visible hampering my goodwill as a seller. My question is , Can we take any legal action as the customer has levied false allegation on us also against amazon as well.