Employer overpaid me in 2017. I received net 20K in bank. Employer asked Gross of 27K. Gross includes insurance/401k/all taxes. Who would pay me 7K back?

[Leonardo]

Deduction is different than what i am paying extra net money. It make sense to deduct in 2019 because i am paying taxes on 2017. I need my  7,000 which i am paying more than they paid. Would IRS would pay be 7k ?

[TaxGuyBill]

Read my comment above.  You should not be required to repay your employer the Social Security and Medicare taxes, and the rest of the $7000 you have already received credit for.  Nobody is going to pay you $7000.

When you do the "Claim of Right" on your 2018 tax return, it should save you some taxes on that repayment.