W: "I noticed D15 had a letter from you. I asked you if they were collecting some and you said no. I would have liked to have sent her one. No need to talk about this. Just wanted you to know"
Didn't know how to "validate" this, because it was completely off.
Validating her feelings doesn't imply agreeing with her facts:
"I get you're disappointed you didn't give her a letter, and seeing my letter to her may have rubbed it in.Correct--the staff didn't request and aren't collecting letters."
I get it was important to you to clarify the facts, so this reply validates feelings then confirms facts.
