Dell wont reimburse me for the 3rd party skin

I brought 3rd party dbrand skins for my laptop. Dell wont reimburse just for one skin. As I still have warranty on my Dell XPS 13 2in1, they are going to replace my bottom cover on it. But will not pay me back for my 3rd party skin that only cost me $15. How cheap of them. I brought the laptop for $1700 and they cant reimburse me with a fraction of that amount. I even had 7 dell laptops in my family and a customer who loves there products. Might move on now, seeing as they don't care about loyal customers.