It is no different than any other business. If you aren't going to be able to meet or keep the agreement than they should be the one contactingu.
However, it does not hurt to call them a week or so ahead of time to remind them, especially if they have a history of being forgetful.
If you like this quilter and her prices, maybe this will be the norm if you continue to use her. If it is unacceptable to deal with this each time, maybe find another one? :D:D:D