I dont deal specifically with NavFed, but they probably the highest ranked CU in the nation. They are certainly the biggest.
In drafting a GW letter, I would make a few simple recommendfations.
Of course, you have to minimaly acknowlege the delinquency payment. First, isolate why the account was held to have been delinquent.
There are two reasons: either you paid on time, but did not remit the min. payment due, or you did not pay on time.
Tell them why either of these events occured, and why it was a single anomoly. Emphasize that this is the one, and only, late ever with them, how much you value their service,and how much the granting of their GW deletion will foster your future business with them. I would not just say, "help me out in order to improve my credit score."
As to who to address it to, they have an accounts management division, or whatever they call it, which handles the reporting of their accounts to the CRAs. That would seem the logical address to obtain.
