Instacart complaint: Unfair Rating

I received a one star rating and contacted Instacart to see if they could tell me why because there was no issue showing on the app. A representative told me a customer stated that they never received their order and in turn gave me one star. The order was delivered, I took a picture through the app like I do with every order I deliver. I told this to the representative. They told me not to worry about it, the rating would be removed. It has been days and it wasn’t removed so I contacted them again. A different representative told me they cannot remove a rating despite the fact that I did deliver the order, took the picture as I am supposed to and the issue didn’t show on my app. Not only is this not fair to me it is terrible customer service. Receiving two different answers and the issue was never resolved. I feel invaluable as an employee and there is no support provided to the shoppers.