Feedback is only allowed if a transaction started. This means either payment or item/service was exchanged. If nothing was exchanged, feedback is not allowed.
I do not see any evidence that shows anything was exchanged in this thread.
https://www.epicnpc.com/threads/feedback-given-revoked.2415583/
If you are still negotiating and the sale falls through, feedback can't be exchanged. Sorry.
Feedback will be removed in 24 hrs unless evidence is provided showing something was exchanged.