If you refunded voluntarily, that is a reason for getting feedback removed and, mentioning Ebay as refunding the buyer should also be grounds for removal.
So, ask Ebay.
How do we remove feedback?
We use automation to proactively remove feedback that goes against our policy. For cases that are not clear-cut, we can carry out a manual review if you request removal through Seller Help - opens in new window or tab. Depending on the situation, we may remove the comment, rat...
If your feedback qualifies for removal, we'll send you an email and the feedback will be removed from your account within 24 hours. If it can't be removed, we'll explain why it's allowed under our policy.
https://www.ebay.co.uk/help/policies/feedback-policies/feedback-policy?id=4208&st=3&pos=1&query=Feed...
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)
