I would be raging. Why would the box say that on the front and inside say something different? like you cant take it apart in the chemist to see the colour. I would make that mistake also. Thats not even your mistake its their mistake.
I think putting a well-worded, punchy complaint right on their FB wall is the way forward. Got me quick results with eBay when they were being useless about a complaint I had. I know it's worked for others too. Companies hate having complaints visible publicly for all to see!
Sorry this has happened hun - I hope they sort something out for you ASAP!