Cash Build misleading adverti*****t.

I saw a tank combo special on Cash Build's catalogue,It was 2 tanks both green in colour, but different sizes. I went to the shop and paid,but to my surprise yesterday they only delivered the bigger one,I had to call and ask about the small tank,then I was told it will be delivered today. Today they brought a grey tank instead of green,and the manager told me that they get them like that from the supplier so there's nothing he can do. I'm not happy about that because now it seems as if their advert is misleading people. If I knew I was gonna receive different colour's I wouldn't have bought the combo instead I was going to buy only the big one because now it does not look nice. Also the one they delivered looks smaller than the one advertised,I doubt very much if it's the correct size.