"Product arrived with missing pieces" and "Product arrived damaged"

I'm not yet very confident with the FTID method, thus I'm trying to perfect myself with the cases in which "product arrived with missing pieces" and "product arrived damaged".
I used to do DNA for a long time, then I stopped it to achieve some goals and now after having lost the opportunity to exploit the lockdown situation, I am here again in this business.

I told to the seller that the "product arrived with missing pieces" on eBay, the seller offered me to send it back to they at their expense and to send me another one new.

I need you experience and creativity. What could I tell them now in this case?
My goal is obviously trying to keep the item and do not pay it.

Thank you for your time.

If you are screwing over an individual seller you can go fuck yourself. Dont be screwing people over man not cool.

As with everyone else, Individual eBay sellers are trying to make a living.

Drop this SE altogether and opt for a company on a large scale, such as (obviously) Amazon.

Okay, thank you.

(25ch)

As requested, thread closed.