It would have shown on the buyers order details the expected delivery dates and if you or the buyer are not in the express post zone that wouldn't have been taken into consideration with the date range showing.

The buyer has incorrectly claimed the parcel took four days when the tracking site clearly shows it took two days. Based on that information I would be ringing ebay and asking them to remove the feedback as the buyer has made a false statement.

I would remove anything from your listings referring to delivery times. Ebay provide that information to the buyer both on the front page of the listing and also under the Postage and Payments tab.