When I'm discussing with a person the route of sending off a phone to be assessed I always advise to take time and dated stamped pictures of the phone with one of it turned on.
This is to be able to show proof of the aesthetic condition of the phone before sending the phone Off as unfortunately damage can occur in transit and I'm sure accidents can happen at the service centres.
I see you did this @nageab but were they time and date stamped too ?
The best avenue I feel is to visit a Samsung Service Centre if one is local instead of sending off rhe phone.
On my own Fold³ the inner screen protector delaminated meaning there was a black line up the centre crease and then bubbles started to appear.
In my instance I carefully peeled the factory fitted screen protector away which does not invalidate the warranty however the caveat is that if the screen is damaged in the process of removing the screen protector then the warranty is voided.
The display was fine underneath.
I left the in-transit plastic protector on my hinge too.
Sometimes with cases if some grit / debris works it's way under the case then this can cause mico scratches.
I'm not saying this was the scenario in your instance.
What damage is to the hinge ? Can you upload a screenshot please ?
Even though you've already escalated this there isn't anything stopping you from asking for your case to be looked at at a higher level.
i.e Not the Service Centre Department but instead Samsungs Complaint Department.
Maybe also look at any relevant insurance you may have i.e Home Contents insurance [ I appreciate you shouldn't have to ]
Are you in the UK ?
If I can be of any further help then please don't hesitate. Take care. 😎
Daily Driver > Samsung Galaxy s²² Ultra 256Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "