BMW REFUSING TO REPLACE MANUFACTURING FAULT

I drive a 220I about just over a year old. Took it to BMW Cresta on 11 July 2019 as the sunvisor on the passenger side is cracking and the buttons on the aircon panel and gear lever section is starting to peel. They told me it is as a result of a chemical being used on my car. I went to the car wash were I have been washing my car for the last 7 years and took it up with them. The gave me a letter from their supplier indicating which chemicals they are using on the vehicles (water based) and that they are washing more that a 1000 vehicles per month. Surely, it cannot be car wash other wise they will have hundreds of cars' button peeling!! I have sent this documentation together with images to BMW Cresta on 24 July 2019, after the vehicle has been there to show them that it is a manufacturing fault so it can be replaced. Kevin, the manager insisted in seeing my vehicle again. I took my car there again on 29 July 2019 so Kevin could inspect it. I was promised that the sunvisor together with all the damaged buttons will be replaced and a courtesy car (will be provided). I sent a follow up mail on 30 July 2019 to make sure that I have everything in writing. Kevin mailed back on 31 July 2019 saying that he would like his technical area manager to inspect the car when the sunvisor arrives. Who do you want to inspect the vehicle next : the CEO of BMW? How many times do you want to inspect it? You replace the sunvisor but not the buttons? The car wash washes a 1000 cars a month, none of them peels, mine peels, so mine is as a result of a chemical being used? Then all 1000 cars must be peeling right? I called BMW SA on Friday, 2 Aug 2019 to log a call. I have not heard anything from them. This is a MANUFACTURING FAULT. Why don't you want to replace it? I am driving a top of the range brand. I am paying R13 500.00 a month for my car. This is a R600 000.00 car. Why should I be driving around with buttons that are peeling? My vehicle is still under warranty. I gave you all the paper work you needed. What is the problem? Seriously? Unacceptable!!