You need to file UPI's (Unpaid item) or you will be charged because you have done nothing to let ebay know you were not paid by not filing them. Plus, the buyer can continue to do this to other sellers (when you file, they get a 'ding' get a few of those and they can only buy 'buy it now-immediate payment required' going forward.
And I highly suggest that is how you list in the future.
