I left US in 2016 for India, but continued working for same company till 2019. They still reported W2s for 2018,19. Now CA FTB is penalizing me for leftover taxes. Help!

CA FTB agent said, US company needs to amend W2s for RSU allotments and provide letter for explanation. I reached out to the US company and they are refusing to amend W2s. Not sure how to address this situation now. Please help.