In my opinion, any longarmer who is doing quilts for pay is responsible for her business. And that means making your customers get what they pay for. (No, they're not ALWAYS right, but do have a right to what they pay for.)
Talk to her. Not a note through a third person. Tell her that you are disappointed and why. She should offer to fix it or refund some of your money if not all. This sounds like more than a "communication" problem. It sounds like she is not as experienced as you were led to believe. The large fold in the backing is unacceptable. Not clarifying what you wanted for a pattern is not good practise.
Either way, YOU have to step up and talk with her before she takes on another client. Give her a chance to make it right.
Just my opinion , as someone who is starting out doing "cheque" quilts.