You purchased Lithium batteries. If you are interstate from the buyer, they would have to be sent by road. They can't go by air. EBay's ridiculous estimates don't take that into consideration. Weekends also count as business days as far as ebay is concerned. Therefore, they will probably take a bit longer than other items to arrive.

Estimates are just that, an estimate. They are not called definites. Did you know that the seller has no control over how long something takes to arrive? Thankfully my buyers are decent people and they contact me via ebay messages, rather than going for the jugular by opening a dispute if there's a problem. Did you know that eBay can read the messages between you and a seller? Therefore, your reason for opening a dispute sounds more malicious than anything.

I hope all this angst is worth it and that you get your refund for $3. Welcome to a lot of people's speshul lists.