They damaged my fingerprint sensor function and take no responsibility

<p>I took my phone in for an ADH premium screen replacement. It is an S7. I paid an additional R3000 for the repair due to a cracked case which I had no problem with. Problem is I received my phone and my fingerprint sensor was broken!! The security lady confirmed to the manager that it was working when I dropped it off!!! They now they me because it has scratches they can't take responsibility for it stopping working. I am so irate because it was working when I dropped the phone how can they not take responsibility for it not working when they were done with it? Will seek retribution from the consumer protection tribunal but so disappointed after many years of brand loyalty from me....my Tv's, washing machine, dishwasher and drier and all my family members phones (7 of us) are all Samsung. Feeling really gutted </p>