Too bad about the decals Igor, it is such a beautiful model.
I have a couple of ideas you might try. First it looks like the decals are hardly even sticking. If this is the case and they are very thick like you say, you might be able to get them off in one piece and re-apply them using Future as a glue. It doesn't look like they will come off in one piece, take a sharp hobby knife or pin and poke hundreds of small holes in the clear decal film where it's silvering and brush Future on, working it through the holes under the decal film. The last resort would be to get some sticky tape and pull the decals off with it and start over with new decals.