If your employer has already remitted the taxes to the IRS and FTB then they don't have that money and probably won't be able to help you.

Waiting until you file your tax return is absolutely an option, and it may be your only option.

When you get a new job, which I hope you do soon, you can adjust your W4 to account for the amount that was already withheld so you would have less withheld going forward for this year. I understand this doesn't help you right now, but I don't see any way to get around it until you file your tax returns.