Faber — Chimney cleaning made my chimney grill go brown

We had asked for a regular chimney cleaning, we had done the cleaning before and the last time they did it, they did it well but this time when they came for cleaning they used harsh chemicals without diluting it (last time they came they had diluted it) which completely made the chimney grill and the sink in which they cleaned go brown but then they were also very arrogant and wanted to leave it incomplete without even cleaning it and at first they just wanted to completely replace the new grills in my house with another old one that they had cleaned previously. we had asked them for a replacement since they were the ones who did the damage but, there has been no response for replacing the grill and the sink for free.