medical payment taken out of vacation payment

My husband was let go from his job mid June. He got paid every 2 weeks and medical was always taken out in each check to equal the monthly payment of roughly $240. Before his layoff he was paid and he received another check shortly thereafter which would have paid the remaining for the month. He was told we would be covered through the end of June. On July 2nd we received his vacation payout with medical taken out. The check was dated July 1st. When he called he was told this was part of June's pay period and that this was correct. Regardless of what month they want to call it, the medical was already paid. They will not return any of our calls for further inquiries. Is this legal and is it worth it to fight?