How do you guys handle negative comments?

How do you guys handle negative comments? Recently a customer created a big scene at my work and yelled at me saying that I was not even speaking english and that he could not understand what I said even though he was understanding and perfectly replying to whatever I had said and also I only had 2/3 stuttering blocks. Then the customer goes on to tell my manager that they should hire someone who can speak English while staring at me. I have been constantly thinking about this incident and it's just ruining my mood. I know people say that you should just ignore negative comments but how do you do it? I just can't remove this incident from my head.