I do my own long arm quilting, so I've had lots of experience removing quilting! As mentioned previously, try clipping the stitches from the back every inch or so, pulling the small pieces of bobbin thread out as you go. I alternate this with 'skinning'. After you've removed a section of bobbin stitches and you can separate the layers, try clipping the threads from under the backing. Basically between the backing and the batting. I would also just ignore the needle marks. She will probably need to press the top before quilting. Often the holes will close if you use steam. I would hold off washing the quilt until it's re-quilted.
My other question is how is she disappointed in the quilting? Was the pattern used not to her liking? If it was poorly done, I would return it to the quilter. She probably paid quite a bit to have it quilted and she should have gotten her money's worth!