Hello My name is Ian ~ I am not on the site constantly so please be patient whilst waiting for responses to you queries
I need you just to do a couple of things for me and then I can further diagnose your fault, if you move the drum by hand does it feel rough and is it noisy? Can you take the top off to look inside? ~ Ian
OK well from what you have told me the belt has come off the drum pulley at the back, it has either just come off, has snapped or the drum pulley (unusual) has become loose. You will need to take the top off to refit/change it or tighten the drum pulley.