Remember sometimes people's criticism comes from racism, but you can take motivation from that to keep learning. Many people don't know that their pronunciation is a bit off. Don't feel ashamed when somebody tells you that. Take a lesson out of it. Keep learning everyday. Note: Sometimes it maybe very hard to change accent, you can just copy native speakers for example from YouTube. Don't give up!

Yes don't let them win! Maybe some of them are a bit jealous that you can speak a foreign language. (1) I swapped this around to prevent it sounding like you were talking about the pronunciation of the word "others" itself.