My experience is that Ebay can take a day or two to reply, but they do reply and they do study the case or complaint that you present to them, they do analise if the matter you present is consistent, and they do take actions. I can tell you by my own experience, both as a seller and as a buyer.
I respect very much their service. They are aware that a bad service can lead into customer distrust and subsequent loss of profits, and they protect themselves very well agains this, resulting in good customer protection as well.
Regards.