You can't use claim of right if it happened in the same year as best I understand it. The company needs to correct box 1 of your W-2. They won't correct box 2 since that represents the money you already had withheld. They may or may not be able to correct boxes 3-6 but if they do, that's money they have to refund to you, it doesn't come back in your tax return.
Part of the company's process to correct this is to file amended form 941s with the IRS (they file a quarterly form 941, you don't get involved in this.)
If they refuse to correct the W-2 there is a process to file your return anyway but it will likely involve getting the IRS to notice both you and them, so better to wait and give them a chance to fix it.
