Get a small horse hair brush and remove the residue in all the crevices were they let it build up. It's a rush job they probably did not mask at all and got polish or lsp residue everywhere. Alcohol will remove the lsp and full strength alcohol is usually not a good idea, dilute with distilled water about 3:1 ratio. The slippery surfaces are just what other's described, whatever product they used is doing that.
I'd personally wash the car properly first before doing anything and see what comes off, dealers are notorious for glazing up cars to hide defects. Live and learn quality details take time or money, sometimes even both.