Company says I wont be paid my PTO due to system error. (That they were aware of)

I recently resigned my company and as such am entitled to my remaining benefits (aka vacation time).

Our company uses ADP for payroll and benefits tracking and has a portal for employees to login and check their payroll stubs and benefits, etc.

When I resigned my portal showed that I had 234 hours rolled over from 2015 and 120 hours accrued for 2016. For a total of 354 hours remaining for vacation time.

When I asked for a confirmation of those hours and when my final check would be I was told that the company was knowingly aware of a discrepancy where the system rolled over too much of the vacation time. Although they had not notified any of the employees.

This changed my 352 hours the system states to 280 hours.
The Company knew about the discrepancy all year. And did not notify or correct the error.
We are told this is the system of record to use, they've had high turnover in accounting but I don't see how that is my problem. (for lack of a better way to say it)