To summarise previous suggestions and include my own - write your own summary of the verbal report she gave, as you recall. If you took notes as she spoke to you, so much the better. Use these. Then send copies out, making it clear that this is from the verbal report to you and has not yet been confirmed by her in writing.
ALso send her a copy and ask her to confirm or refute. Yu could even add, "If I don't hear form you, I will assume you are confirming the truth of my recollections."
Put it in a friendly way though, don't make your letter seem confrontational. Give the impression that you know she is busy and has a huge workload, you are putting in writing for her, to save her form having to rush to do the job herself. You're only trying to help. But you DO need some confirmation that she did receive your message, so either send it registered mail (which I personally would not do, with this - it makes it too obvious that you intend to use this legally and she has dropped the ball) or send it via email with "verify receipt" enabled. You then should have proof (unless she chooses to not verify, and tat refusal will speak volumes) that she has received your email. If she then fails to respond, then you make it clear that she failed to respond to a letter which indicates tat failure to respond equals confirmation of content as accurate.
Often just sending an email like this, even worded politely, can get interesting and enlightening results.
Several reasons I can see, for her behaviour:
1) she has been scared off from being involved, she now realises this is a potentially contentious issue and she will make enemies whichever way she jumps.
2) she has been actually told to shut up and not give you anything you can use - she may have been told she will never be asked to do reports again, if she gives you what you want in writing and she now is trying to backpedal on what she told you.
3) she may simply be lazy and overworked, and wants to leave this and move on since she's already spent more time on it than she has been paid for.
Marg