Istore Kolonade Bad treatment

On the 11th of March 2025 I went to Istore Kolonade mall to trade in my phone, Unfair treatment of the store, the store name is istore Kolonade mall, I went to the store to trade my iPhone 12 and I was shown an amount of R5600 on the screen and which I got interested in selling the phone and after they are busy with my system they decided to take the amount down to R530 and which after they damaged my screen protector and the store manger told me there is nothing I can do about it I have to buy a new screen protector at the store and him being the manager I wont get a screen protector from him and there is nothing I can do. I tried to reason with him and he also said that’s I can even take the matter further and nothing will happen. Please assist I’m hurt by the service that the istore gives to black people, there was a Chinese person in the store and they gave fine the best service but when coming to use blacks they even took their time To assist us and they were slow with their system and they wanted to offer me R530 for ma iPhone 12 with no damage where they claimed that’s the phone has damaged mic and Facebook audio. Please assist.