You can't blame ebay entirely for buyer's interpretation of the estimates. After all, an estimate is exactly that - an ESTIMATE. Plus it does say it's only an estimate!
Delivery: Estimated on or before Wed. 21 Feb. to ... (postcode)
There's a little question mark at the end of the above bit and if anyone clicks on it they see this:
Delivery time is estimated using our proprietary method which is based on the buyer's proximity to the item location, the postage service selected, the seller's postage history, and other factors. Delivery times may vary, especially during peak periods.
Anyone with half a brain should know they're only approximate dates, even without reading the extra bit above.
