Don't believe the 4 star rating

Taking my wife on a birthday weekend away, we booked into the Emerald Casino hotel. The room that we requested was a non smoking room, however all we could smell in the room was smoke. We complained twice about this at reception and on the 1st complaint the room was sprayed with what I would assume is a odorising spray however it was non effective. My other complaint besides the dated look of the room was that the wallpaper appeared to be coming off at some places and was dirty. There is no way that this is a four star hotel. I would have expected at minimum that the room would have been swapped out during the stay.