This is for an item I have sold in the last hour. I have 5 day despatch and use other courier 3-5 days.

How can ebay possibly tell me to post by the 15th Feb, yet tell the buyer it will arrive between 13th Feb (2 days before I need to post it) and 16th (only 1 day after my lastest despatch time, on a service that takes 3-5 days).

It doesn't work - plain and simple. If you can't see that, and the shipping team can't see that ... well, there is just no hope, is there?