If the problem was the paste, then I’d say warm water followed by a scraper should work. I had a similar problem but with drywall. The paper had adhered so tightly to the drywall that it actually removed the outer layer of the drywall! No matter what I did, the walls were left looking gouged. Spackling on drywall compound to fill the gouges is the only reasonable solution. I’m not sure what to do about plater, though.
If a wall has never been painted before then it needs to be properly prepared prior to using wallpaper!