Don't be Naive.
EBay is CHOCK FULL OF SCAMMERS.
The legitimate sellers will have no issue refunding or replacing and make no issue of it.
But it is your responsibility, your 'duty' to immediately communicate issues to the seller through ebay messaging system and to take action exactly when the ebay 'claim window' opens.
Due diligence is your responsibility, and Scammers rely on the exact same hesitation that you have exhibited, to leverage the scam.
I'm guessing you are / may be about to learn a hard lesson, through the protracted dispute resolution process, and your seller feedback should also be honest and reflect the events. If the seller scammed, you should be specific in your feedback as a warning to others.