Can you sue a reviewer for negative feedback?
Reviews that are opinions are protected under the first amendment for free speech. However, if the review includes lie(s) that you can proof, or defames your business you may be able to sue them.
An example of each may be:
Opinion: The item was poor quality and not worth the money.
Potential defamation: Item is not handmade and is a cheap mass produced item that is not real silver.
Notice the difference?
If the potential defamation review can be proven as a lie and indeed is handcrafted of real silver and it hurts your business you may be able to sue.
It is a good idea not to respond to the review in anyway that can in-turn harm yourself. Be careful not to slander the reviewer or it may be used against you in a lawsuit.