My Mandarin is not standard and I am constantly being laughed at by a colleague. How do I fight back?

I am from Chongqing. I don’t know if you have heard of Trump. It makes me speechless. My hometown is in Northeast Chongqing. People in several counties over there don’t speak h or f. Well, we say "eating" is called "eating", "recharging phone bills" is called "charging hui", and "having a meeting" is called "having fei", so you know that people from us will be laughed at when they talk in Chongqing. Even the locals in Chongqing will laugh at the Chongqing dialect of our people, but so what. I feel that there is nothing to fight back when being laughed at. I can only do it well and let him shut up his mouth that likes to laugh at people. I came to Chongqing and spent a month to correct the pronunciation problem that I had for 20 years. People will only recognize that I have an accent when I speak, but they will no longer laugh at my indistinguishable hf, so all you have to do is practice Once you learn Mandarin, it’s not difficult. Some people can learn English by themselves. How difficult is Mandarin? Besides, you won’t suffer a loss if you master it, right?