There is nothing in the very brief feedback the buyer left that would make Ebay remove it.
There is a process when buyers don't pay. You wait 4 days, then cancel the sale of day 5 with the reason 'buyer did not pay'. Any feedback left after such a transaction would be automatically removed.
"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)