Lesson 1 - Don't sell computers or phones on eBay. Or even online without pickup only stipulated. Which you can't do on eBay.

Lesson 2 - if the buyer opens a Not as Described case you will have to pay for return shipping or eBay will refund the buyer from your money and tell them to keep it.

Lesson 3 - apprise yourself of the pitfalls of selling on eBay BEFORE you try to sell scammable things.