Employer overstated California income tax for RSUs

[pleasesendhelp]

Last year, my RSUs converted to common stock so I owed ordinary income tax. I lived in California for the first 15 months of my employment and therefore owe some CA tax. I've since lived in Florida for the remaining time. However, my employer's Workday system had my move date as being 51 days later then my actual relocation date. So my employer's accounting team overstated my California taxes by 51 days. I've tried many times to get them to correct the W2 but they are refusing because they will only go off of what their internal system tells them for my relocation date. I even gave them formal proof of my Declaration of Domicile showing the correct date.

I'm not sure what to do here. Is there another way to reclaim the overstated taxes to CA or do I need my employer to issue me a W-2 C?

[AmyC]

A corrected w2 is easiest for you but not always attainable. If you can prove you actual move date, adjust the wages on the W2 section (federal entry) to the correct amount. Boxes 15-17 can be adjusted to reflect the reality of your situation. The state will probably send you a letter saying you underpaid. You will have to reply with your story and proof. Then CA will decide if they agree with you or if you owe.