Wedding problems

Before covid my sister was getting married and we picked a theme for the bridesmaids. At first we picked the same outfit for everyone but they didn’t want that they wanted freedom to get whatever style dress they wanted. So we said ok but one part of the dress we are having the same design but different colors. (This is a traditional cultural outfit not an American dress). So they agreed. Now the wedding is being planned again so we were about to order the things. So now the bridesmaids are complaining that the outfits they picked have become to expensive and then the additional part that we want is too much. Even though this is how much we spend on our other friend’s wedding bridesmaids outfit. They want to change the part of the dress so something cheap. But the argument with this is that they knew this was the constant factor in the bridesmaids dresses and they chose how fancy the overall outfit is and got the price. Bride wears color and the bridesmaids were wearing white with one part (that was the constant) difference colors that they can choose. They are saying this is inconsiderate and unfair especially since they have two other weddings to buy things for now coming up in the year. Who is being unreasonable? They knew this part of the dress was the constant and now they are saying they want us to find something cheaper. We are mad because they knew about this and splurged on the outfit themselves? I ended up saying just do whatever you want no theme anymore and they are saying we are unreasonable.