My personal opinion, as someone who does quilting per contract, is that this "pro" is not taking her job seriously. If she were her own boss, she should fire herself.
When one gives a deadline, and accepts it, it is a contract.
Not being able to honor that contract, without adequate reason or communication, is inexcusable.
I think you should decide how much you want her to work for you.
If her inability to meet your requirements is causing you to lose sleep, you need to find another quilter.
Sorry to make it so cut and dried, but really, it is.