Replacement iPhone case is discolouring and wearing off

I contacted Apple previously regarding a problem with my original iPhone case, which was discolouring. Apple replaced it with a new one in September.

Unfortunately, I am experiencing the same problem again. The replacement case has already started changing colour and looks as though the surface is wearing off.

I take very good care of my phone and its case. I work in a clean environment and the case is not exposed to dirt or harsh conditions.

I am disappointed that this has happened again, especially as this was already a replacement.

My previous case reference number is ***

Could you please look into my previous complaint and advise me what can be done? I would appreciate a proper solution.

[Edited by Moderator]