Living Room was painted a few days ago with vinyl matt. We then had some work done on repairing the floor. After that was finished I noticed some yellow streaks on the paint work and got a damp cloth to see if it would come off. All the paint on the wall started coming off - it had turned back into liquid and the yellow spread out into a big patch. Went to Brewers for advice and he said this can't happen with vinyl matt. What has happened and should I just paint over it?