Cracked LCD Replacement invalid - different OS

I have a S4 and needed a screen replacement with the ADH warranty. The screen cracked but now Samsung does not want to replace the LCD with a weak excuse that the OS loaded is not OEM. I dont understand how this affects a LCD that has cracked due to falling literally 30cm. Seems to me the whole ADH is a farce to ***** customers into purchasing their devices. The excuse is weak as its a screen replacement and not an OS reload or any issue related to software. Even the Google Play Edition runs the stock android OS and allows for rooting, whats so different in this case? I am extremely disappointed by Samsung and did not expect to be cheated into purchasing something that does not exist (ADH is a joke). And just to top it off, I sent my device in Monday (02/03/2015) and nobody had the decency to let me know what was happening, i had to call today (06/03/2015) to find out about my device. The service is rather appalling, and that's not even mentioning the wait it took to hand the device in.