Employer reports wrong SSN on W-2 form last five years. Now they shut down, just discovered problem, they say they wont fix it

I just discovered my employer recorded my SSN wrong for the last five years. Only one number was wrong and I never caught it on my W-2 Form. The business has closed and I discovered it when filing for unemployment benefits. Neither my tax man or the IRS(fed or state) have caught it either though my returns have the right SSN on it. My employer is winding down the closing process and when i called them today they said they were not inclined to pay ADP (Payroll Processing Company) to fix the problem and reissue the correct W-2's. They said since it has been five years I should have caught it and they are not responsible for the fees. They say it will be $2500.00 to resolve. Do they not have a legal responsibility for correcting this problem? This affects my SS benefits plus any issues with the IRS for filing a wrong SSN on the W-2. What can be done. They will complete closing by January 31st and I have to move fast to try and resolve.