An update: I called the main office and presented my question to the person who answered. She told me that I was in a position to submit the appeal, so I did. After it was received, they sent me a letter clarifying what specifically had caused the denial. I sent a letter and supporting documentation in response. This was in September, I believe. Now, I'm just waiting to hear back from them.

Thanks to all for your responses. I hope to update soon with some positive news.