BuyFromEU

Ok so this is not entirely answering your question (as other comments already provided the alternatives I'd give for cola) but I had this issue as well and tackled it another way:

I looked into buying other types of soda like Ice Tea Sparkling. I personally really don't like any cola that's not coca cola but have just replaced it with Ice Tea Sparkling and Lemon-Lime drinks from the store brand of the store I shop at (Initially Lipton and Sprite, now store brand since my move to BuyFromEU). Perhaps this could be interesting to you as well.