Did you get any resolution to this?
Support sent me to this location which sells replacement boom mics for their HS series headsets but they're not in stock.
https://www.corsair.com/us/en/Categories/Products/Accessories-%7C-Parts/Gaming/Gaming-Headsets/HS-Series-Mic-Boom-%28for-HS50-60-70%29/p/CA-8910042
I'm curious if you found a good replacement mic that wasn't from Corsair?