Credit card or prepaid card — NAVY FEDERAL CREDIT UNION (NC)

Problem with customer service. I have had my credit card with Navy Federal Credit Union for over 5 years and have been a member forever 14 years. My credit card expired in XX/XX/XXXX, and I contacted Navy Federal asking for my new card. I was told that my credit card account did not meet their standards under review, and that my account had been closed. I was asked what criteria was used to make that determination, and was told that they didn't know and could not transfer me to the credit card department in an effort to keep the credit card department unbiased. This is the same credit card that I talked to multiple times in the past. They told me that they sent a letter to my address, but I never received it. It was not sent certified mail, and they have no proof that I received the letter