Ghosting bridesmaid

So I felt obligated to have my fiancé’s friend as a bridesmaid. Long story short she helped him propose to me at the perfect place and time. I thought we were friends and now I’m unsure where we stand. She was dating the best man and found out she was pregnant after I asked her to be my bridesmaid. She seemed like she was been distant and she hasn’t been getting anything together in a reasonable time frame. Normally u want to get ur dress for the wedding as soon as possible so it would be there in time for the wedding. I get married on June 19th. We looked at dresses for everyone February. We found her a dress and I was willing to pay for it. She said no an tht she would pay for it tht next week. Two months after I ask her if she ever got her dress? Did it fit? What needs to be done to it so it would fit her perfect? She tells me she hasn’t ordered a dress yet and that I’m over reacting. She wants her dress tht she tried on at David’s bridal , I find out tht she can’t have tht dress because it’s now on back order and it won’t be in till after my wedding. I said ok I can buy u a dress , pick another out and I’ll have it shipped to ur house. She says no again and picks a dress online from David’s bridal tht she never tried on and buy it and has it come to her house. She tells me a month later tht she got the dress and will have alterations done tht next week . She said she knows a place. I said ok and trusted her she was gonna have it don. And told her if money was an issue I can pay for it. Now it’s 10 days before I get married and I have not been able to contact her at all. I find out tht her and the best man are now separated and aren’t talking to each other . I try and text her, her phone is apparently out of service. I try and ask the best man if he knows anything he says she hasn’t gotten her dress fixed yet . Keep in mind she told me she would a while ago. They tell me she also is now 6 months pregnant.(which means she isn’t wearing the size outfits she normally fits in and tht her size 6 dress probably won’t fit now). I am so upset I try and contact her every form I know how to asking if she would like me to have her dress fixed, my family sews and can literally make a dress fit her and have the bottom hemmed. I know if someone’s phone is turned off . If u have WiFi of any sort u can use apps to message Thru. So I make sure to message her everything on Snapchat. Because she and the best man broke up and are now separated , she has unfriended me from Snapchat. I know this because , it notified me when I tried sending the messages to her. I can’t get I contact with her to even know her address to meet her or send her the invitation. I am now emotionally hurt and mentally stressed. I want the public’s opinion should I replace her? I have an actual friend who is willing to be a bridesmaid. We are able to find my friend an emergency dress.