Rant: Client called me a racial slur

I know I’m not suppose to take what the kids say to heart when they are upset, however this one is making me view this client in a different and negative way. The kid is white and I’m black. The client got upset that I denied access to a bike that was built for 2 year olds (client is 8). Client angrily threw the bike and called me the “N” word with the hard “er”. I know he truly doesn’t understand what the word means but it hurts a lot to hear him say it. For the rest of the session I tired to keep a positive upbeat mood, however it was difficult.