We quilt a lot of their pieces, and I have never heard anyone complain about that before. We do hand quilting at my church for others and they like doing the preprinted designs. I personally like doing them because I don'thave to mark those!
I am so sorry that it happened to you. Did they offer any suggestions about how to get the marks out? Are you just going to have to live with them and let time take care of them?
I would ask some of the older ladies what they have done?