So, this:
Your statement fully disclosing the details surrounding the sale/barter transaction referenced above
This SWU was a gift
• Copy of all communication between yourself and the purchaser You have already rec’d screen shots from Mike in regards to our conversations
...doesn't really seem like a satisfactory answer, for 2 reasons:
1. "This SWU was a gift" didn't come close to a full disclosure of the circumstances, and probably came off as evasive, and
2. Referring to screen shots sent by the other person (you?) didn't actually satisfy the request. The analyst likely wanted documentation from both sides to see that the story was corroborated, so telling him "you already have it" wasn't sufficient.
In my armchair opinion, anyhow.