From experience. (Took close to 3 months mind)
Bought a S21Ultra 1gb in Phantom Black during the unpack with the smart case.
Phone delivered, all okay.
2 maybe 3 days in found the case had scratched the screen.
Contacted samsung shop, (yep, Philippines). The agent said to return for a replacement and sorted out tye return and told me the replacement would be automatically sent on reciept....
It wasn't.
Emails, chats etc then went on and on... All evidenced by email and the samsung zen desk system.
Phone now out of stock, yet constant email notification of it being in stock on the shop (go figure...)
Escalated the matter to the agents manager and then to the managers, manager... Who confirmed that while they may have a phone in stock, the warehouse will prioritise it going out to a new customer over a warranty replacement (how true that statement was I don't know, but it certainly fitted the apparent circumstances).
Agreed a refund as the phone was now showing as out of production (they do this with the top model).
Now, gets interesting... To get the refund I had to send back the gizzits that came with it. I went ballistic lol, not my fault they didn't replace the handset etc... More emails, cooling off period on both sides etc and an agreement that I would send back the gizzets (which I did) and they would refund the phone (which they did) AND issue a credit note for the shop to value for the gizzets (which they did).
As I had already bought another one (with more gizzets lol) the Credit Note bought the wife's Sam 4 watch!
So, for me the answer was...
Be polite to the agent(s), it ain't their fault, get them onside (to be honest they are pretty clueless and are only reacting to what the screen says in front of them, they are not in the warehouse where your phone is or the stock is).
Be persistent (I can be like the pervibial 'dog with a bone' if needed, I don't give up).
Be fair (it works both ways, if they had sent say two sets of buds instead of one they would have had one sent back, always treat folks how you would expect to be treated).
If it needs escalating, then do so but do it nicely.
Persistence pays off....
Current Phone S24 Ultra (1TB)
Previous phones S21 Ultra, S22 Ultra, S23 Ultra.