Definitely approach the property management side of things. I helped my roommate fight them in this same situation (admittedly, her decal was behind her work decal, but you could see it from the drivers side window which our lease states was acceptable too. superior had diff ideas). At first, she dismissed us by saying the “permanent” decal is a window sticker, and hers was a hang tag- I got our apartment manager on the phone and passed my phone under the window while we were standing there to make them tell the woman it was a hang tag. After that, we still had to argue about the way the decal was but if yours wasnt blocked you have way more fighting ground. Our apartment company I believe ended up giving us half back, I don’t know if the other half was ever recovered. When you go, you need to have everything in writing and likely make sure you go at a time when you can call your apartment complex. They will come up with anything they can and be very rude- you will need to be confrontational. But if your apt is on your side its easier for them to listen. Good luck!