The only explanation possible is a broken belt
Take off the right hand side panel looking from the front.
Then take off the small square cover on the back in the middle and undo the pin from the bearing unit.
Then lossen the screws for the left hand side panel on the back.
Then pull the drum forwards from the back and slip the belt round the drum from there.
Then fasten the left hand side up and refit the bearing pin at the back.
Now for the hard part. You need to now strech the belt down and onto the motor shaft.
I use a piece of wood and pull down on the belt and put the end of the pipe onto the motor shaft and slide the belt onto it.
Now getting the belt onto the shaft is the hard part as they are strech belts so when new seem way to small but it will go .