It is not a change of policy.
Ebay has always stated that you can't open a case through Ebay for an item after you have opened a case with your payment provider.
I don't know if Paypal will be able to help as they will be able to see you opened a case and subsequently closed it, but you now want to open a different type of case for a new reason.
"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)