Hi , just wanted some advice , I've just spent a month redecorating our hall, stairs and landing , the walls had been lined with paper and a matt emulsion on top, I bought Dulux washable matt as I wanted a washable surface, but after about 2 weeks of completing project I went to wipe mark off wall with a damp sponge and without even using much pressure the paint came off the wall and the previous colour is now visiable, tried another area and the paint is coming off the wall with ease, really anoyed about this as you can imagine, has anyone got any ideas as to what is happening, as really do not want to have to repaint, any advice would be gratefully recieved thanks