Our painters painted water-based primer over oil-based paint, apparently without sanding first. Then they textured and did the finish coat. The layers are not adhering well (I can scratch it all off easily with my fingernail to get back to the original paint), so we asked them to strip the layers off again and redo with an oil-based primer. They are saying that they can just put oil-based primer and a finish coat over the current layers without stripping first. We don't think this will adhere for very long. We're also a worried about mold growing between the layers that aren't adhering. Any advice on whether the painters' solution is an acceptable option would be GREATLY appreciated!