I'm so sorry you had to come here with a bad experience. Are you a quilter yourself? It is always possible to undo all the work and redo it, but I usually have learned to live with my mistakes.
A picture would help. It might not help, but trust me I know the devastation of opening up the washing machine to a quilt just ruined visually by running dye...
Typically dye loss and shrinkage results are very difficult to undo, while there are some thing we can do to mitigate bleeding dye damage, no real way to get the color back in once it has escaped.. There are products and techniques you can use to stabilize further loss, but no way back to prewashed condition -- even if you took everything apart.
Many people deliberately do not prewash because they want that puckered effect after washing the completed top. If you are sure the batting is cotton, you can iron it. If not sure and it is poly, that could give you even more irreversible damage so maybe try small test on the back side. You still might not get what you want after ironing. Other than that, the answer is to take out all the work and re-do it, but again, the fabric is not going to return to being unwashed.