Losing vacation due to company bankruptcy---are there federal laws regulating how vacation is accrued?

Wyoming based, filed in Texas.
I had accrued vacation time using the accrual method of my company (which accrued vacation on my anniversary date) of 2 weeks. I was told to file a proof of claim with the Texas court for this amount, which I did. Recently I received a letter from my employer telling me that "It is FIRM's position that federal bankruptcy law requires that vacation ay be accrued based on the actual time worked at FIRM which method differs from FIRM policy. Therefore, the accrued amounts contained in this letter may differ from your records but comply with federal bankruptcy laws and case precedent.

The letter indicates that my pre-petition amount is $0---losing over $2600---

Is my current proof of claim filed with the court still valid or would this letter overwrite that?