Removing feedback

[backlogger19]

 I was wondering what the policy is in regards to removing feedback.

For some background info - 

I left negative feedback for two reasons: 

1: I never received my item, and finally got my money refunded through both a case and an appeal to said case.

2: The seller was extremely rude and treated me as if I was stupid.

The seller was furious with me and my negative review, and he/she let me know through a message, thanking me for the "s****y feedback" and telling me to grow up and learn how eBay works, to which I replied why I left it.

They messaged me back and told me that the feedback will be gone in 24 hours, that they "did nothing wrong eBay refunded you I still got paid lol LEARN eBay."

I'm concerned with this because I feel that feedback is and should be a permanent thing, and is a warning to other buyers/sellers, and should not be able to be so easily absolved. Can he/she do this?

What are other people's opinions on this? Am I being fussy about it or am I justified in my thinking?