Buyer left negative feedback without payment

Hello,
What would be the best steps to take if buyer has left a negative feedback, but he haven't paid for the item. Also can't open yet unpaid item case cause it has not been 2 days yet.
Already contacted with user but no response, maybe could be competitor trying to sabotage my ebay account.
What would be the best steps to get this feedback deleted or revised?

Call Ebay they will remove it for you. Also add the buyers name to your blocked buyer list.

Contact ebay

eBay is pretty good about removing feedback in situations such as that.
Just give them a call, their support team is not that bad.