Have you spoken to her parents?  Perhaps just go straight to them and say you've been trying to get hold of her for a week and you need these details now or she won't be able to be bridesmaid.  I'm sure they will be able to get her butt in gear x  Would it upset you though if she didn't want to be one which is why she's avoiding you?  It's a delicate age isn't it where you find everything embarrassing!

I have been trying to get hold of one of our bridesmaids for a week or so.  She doesn't live near and we are having the dresses made so I need to get her measurements to give to the women making the dresses.  I also need to get her shoes.  She is not returning texts or calls so I am going to send her a text tomorrow to say that if she doesn't make contact by Friday then she will not be able to be our bridesmaid.  We get married in 2 months.  She is 14.

Do you think its a bit harsh or acceptable?