How to define if iPhone was activated and when?

Question

My friend is living in Russia (I myself in Canada). Recently she bought iPhone in the shop. When she opened the box she found an old used iPhone there.
Management of the store refused her to return the product.
She put complains to police. Now she is trying to prove that the used iPhone  she received was activated before she bought it.
How she can define when purchased  iPhone was activated initially? (She has iPhone ID on the product).
Where she can file a complain about switch of the products? May be Apple is interesting to know about such cases?
Thank you.

Answer 1

Put the serial number in here: https://selfsolve.apple.com/agreementWarrantyDynamic.do
Since the phone has a 1 year warranty from the original date of sale, you should be able to tell when the phone was originally sold based on the end date of the warranty.
There's nothing Apple can do about it. The gray market for iPhones is huge and it is not necessarily illegal to re-sell an iPhone that was privately purchased.