I would take my time and gently rip it out. Rip on the backing so that any mistakes would be on the back and the batting. I have one that the back was ruined on, and that is what I plan to do to it. I don't get stippling or anything really small on my quilts though. I get things like vines and clouds and figure 8's. Basic stuff.
I probably would have also told her she need much more practice and I did not want to pay for it, or at least not pay full price. No way I'd pay full quilting prices for my quilt to be ruined. I can ruin them for free myself!