seller wants feedback changed, and gave additional refund

[gigagranny]

Can you tell me if it is a policy violation for a seller to give an additional refund, and then ask for Negative Feedback to be changed?

  (Yes, this was additional money, over and above the full refund issued)

I accepted the additional refund, because I had to buy another book before the full refund was received - at a higher price.

I thanked the seller, and did a feedback follow-up, but got another email from the seller asking me to revise my Negative feedback.

I responded by telling the seller that I did a follow-up feedback, but informed them that there was no option given for revising the

original Negative Feedback.

I still think the seller's actions during the transaction were fraudulent, so I would not change the Negative even if given the chance, but

I would add a comment about their apology and additional monetary consideration I received.

***NOTE***  After I posted this question, the seller has been sending daily emails - (I'm quoting some of their words) "We still waiting for your action.".

             The tone of some other messages has gotten almost threatening, so I called eBay. 

             After reading the messages, the representative agreed that this was "Feedback Extortion", and referred it to the "Internal Resolution Team"

             for a "Priority Investigation", which could result in the seller's suspension or removal as a seller.