Just keep harrassing the customer support (best via email and daily if possible) until they are willing to give you the color you like. And give em a phone call too (multiple times a day). I mean for 999CHF you should be able to chose what you get and not play the lottery.
I tried again (now that the truck is cheaper), but was not more successful this time. I've been told it is an "assorted product" (whatever that means) and they don't know and can't check which color they have on stock. Quite annoying and surprising. I would expect them to know what they order from their suppliers, especially for something that is quite expensive.