Oh thank goodness for that! I'm so happy that you've got them!
Definitely try and get some money back if you can, however tread carefully, as whilst she clearly doesn't have great customer service or time management skills, she HAS provided the service that you booked her for.
If I were her, I would give you a discount as a goodwill gesture, but if she refuses, I'm not sure you would have a legitimate claim. If she does agree to give you a discount or partial refund, be sure to get it in writing.
If she refuses to give a discount - well that's what feedback and review sites are for.
The main thing I would say though, is try not to get so caught up in this that you lose sight of the big picture. You have your flowers and they are what you wanted - go out and have a fantastic time at your wedding!
Best of luck for your big day! X