Damaged Mosaics

I bought over 20k in tiles and mosaics on the Nelspruit branch a couple of months ago to refurbish a house. A couple of days after installation on a specially expensive mosaics (at least to me) that have mirrors and glass on them we noticed that a few of them where getting something similar to rust on them and those mirrors where all brown (on a all white shower floor looks terrible) Please note that only around 20 out of more then 100 hundred where getting this problem. I contact the branch and send pictures of it and the sales person told me that they would reply asap to my email. A couple of days later I traveled from Mozambique to Nelspruit with a sample of the mosaics with the problem. Upon my arrival the sales person, Mr. Eedemar told me that management told that the mosaics didn't had any problems and they could not do anything about it because they did not sold me the adhesive and grout. I told him that only a few had the problem so the grout was not at fault and if these mosaics needed a "special grout or adhesive" Italtile should have advised upon the sale, which they did not. What made matters even worse was that they didn't even requested to see the sample. After that I went to CTM (which belongs to the same Group) and showed the mosaics to them, on which they immediately said that the problem was with the mosaics and that they did not believed that Italtile had given me that answer. I then went to Tile Africa, Bathroom Bizarre and showed them the Mosaics and all agreed that the problem was with the mosaics. I specifically went to Italtile to have good quality products and peace of mind, since I need to cross borders I rather pay extra for that, which I did not had. If required I have the email exchange and the pictures and samples with me. The mosaics where not cleaned with any special chemicals beside tap water.