I think you did the right thing telling her. IMO if the bride expects the bridal party to pay for everything, they should have some say in what's going on. For my wedding I told the girls this is the colour, as long as you both look nice then you pick the dress. Turned out they both wore the same dresses anyway. With shoes I just told them to wear open toe black shoes (they were wearing black ****tail dresses) and the jewellery I got from a cheap shop and it cost me about $10 each and still looked really classy.

I don't think it's fair to not let people have any say what so ever in what they are wearing if they are the ones paying for it.