Kilimanjaro Sofiatown - Faulty Tiles - Consumer Complaint for CTM Head Office

I recently bought about 85m2 of tiles from CTM Worcester. My tiler installed about 25m2 and when I went to check on him I had an issue with the skewness of the spaces between the tiles, the corners didn't line up. He then informed me that the fault is with the tiles themselves. The tiles should measure 420x420 but when I measure it only ONE of the four sides of the tile is actually 420mm. The other three sides differ between 417mm to 423mm on one tile. How are you supposed to lay tiles square if the tile isn't even square? That's not the only problem with the tiles, on one of the sides the side is convex in space when it should be a straight edge which makes it more difficult to line up corners. This is really unacceptable. You are selling reject tiles as a-grade tiles. Unethical! What am I supposed to do now with the already installed tiles and adhesive and grout wasted on substandard products!