If your buyer has opened a case, your money will be on hold until the case is resolved.
Has the buyer opened a case because they haven't received their item or because they want to return it to you?
More information will mean better advice.
"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)