You have not given enough information here for us to be able to offer help plus you haven't done enough reading about eBay's Money Back Guarantee for buyers.
You ordered on Wednesday, the 24th. There was an estimated delivery date in the listing. Was that actually the 26th, two days ago, per your information posted here?
If the 26th was the estimated delivery date as seen in the listing, and today's the 28th and you still do not have your package, then you COULD open an item not received case today; however, given recent issues with delays in the mail, would advise you give your package until at least Monday, the 29th, or even just a little longer than that. Per the MBG, you have 30 days past the estimated delivery date to open an item not received case with eBay.
Speaking of the Money Back Guarantee, it's seen in every eBay listing and offers very good protection for buyers if/when a transaction goes wrong. Now would be a good time to read it.
Also, since Amazon has its own delivery system, it seems reasonable that they would have more rapid delivery. Comparing Amazon to eBay is an "apples to oranges" situation.
Finally, regarding "what is your excuse for untimely delivery": None of us are your seller so we do not need to offer an excuse for untimely delivery. The culprit could quite possibly be the USPS which none of us have any control over and which apparently is still suffering.
