HOW CAN I REMOVE THE REAR PULLEY AND FIT NEW BEARINGS?

INDESIT 822R WASHING MACHINE. THE DRIVE BELT HAS GONE SLACK WHICH COULD INDICATE THAT THE MAIN DRUM BEARING HAS GONE. HOW DO I REMOVE THE NUT TO REMOVE THE PULLEY AND GET ACCESS TO THE BEARING. I HAVE TRIED BUT THE NUT WILL NOT BUDGE. IS THERE A METHOD TO UNDOING THIS. ALSO WHERE IS THE BEST PLACE TO GET PARTS. ONE ADVERT QUOTED £144 FOR THE BEARING SPIDER.
NEARLY AS CHEAP TO BUY NEW