Uber complaint: Untrue feedback and no line of communication

I have been using Uber for a number of years with over 200 trips. I am also a healthcare provider and have recently been using them a lot as I have moved to a new city. I have now received a second email from Uber giving feedback that I was not wearing a mask in the car. I have NEVER not worn a mask, I live in a mask for pity sake I am in the hospital all the time and it is law here to wear one. When the first mail came through I thought ok, maybe the driver was mistaken, it was dark and I sometimes wear a black mask but when a second warning email arrives with NO ABILITY TO RESPOND NOR ANY SPECIFICS ABOUT THE TRIP OR DRIVER this really starts to seem like extortion. I gave one driver a poor rating because he drove like a bat out of hell upset that he had to drive us all the way from Dubai to Abu Dhabi but for the rest of it have been quite civil about the small things until now. I cannot understand how there is no way to contact the company other than pre-determined menus?