I contacted an ERISA expert, on the off chance that their acknowledgement that you sent in the paperwork on a timely basis but their subsequent refusal to honor it, constituted an ERISA violation. Here is her answer, complete, word for word, and in total:
Under ERISA they are required to follow court orders ... they are
standing on a technicality that the order was not received within a set time
frame (which is idiotic, but probably within their rights). He needs
his lawyer and the court to direct them to get this done. If his lawyer
is not returning his calls, there are other lawyers.