I would take a strip only of the same material and have them re-do the embroidering for free making sure this time they stabilize the fabric. Then take a piece of batting and cover the strip with the embroidery and applique the new strip over it. It will looked raised but will cover what looks like is impossible to fix otherwise. I don't think a raised embroidered strip will look unplanned it stands out anyway. Next time you want to embroider something on a quilt just take the fabric piece you want embroidered. And then use it as planned. The person at the shop might have had a hard time positioning the whole quilt top although it shouldn't be a problem for anyone with experience embroidering.