Bridesmaid Lied About Ordering Dress

I am getting married in May and have asked two long time friends and my fiance`s sisters to be my bridesmaids. 1 friend and the sisters have been very helpful and supportive in the process; but I`ve sort of felt as though the 4th bridesmaid (other friend) has not really been all that interested. Everyone is busy, so I didn`t think much of it.

A month ago, I went with the first 3 to pick out bridesmaid dresses from David`s Bridal, but had to go with the 4th the next day because of everyone`s work schedules. She said she wanted to order the dress from a David`s closer to her, which was fine.

A few days ago, I asked #4 which store she ordered the dress from - and she responded with a location that doesn`t exist! So... This led me to discover that she never ordered the dress!

Now we`re coming in on the end of March for when her dress would arrive, IF she ordered it. It sounds to me like she really doesn`t want to be in the wedding... Which is fine, now it`s just really awkward!

And I`m really hurt that she lied to me... I mean.. What if I hadn`t asked? I never would have known!

What do I do?!