I did not know that there is a word for this behaviour: „Mansplaining“.
I really hate this. This happened to me, too. Recipe against it: Learn a lot about the topic, prepare yourself for the meeting (better than the others), speak with a clear voice, stay calm, and continue to speak with a firm voice.
People may think that you are arrogant, but so what?!
I’m a scientist and I believe:
„Scientists have an independent obligation to respect and present the truth as they see it.“ (Cited in „An inconvenient truth“)

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