SERVIS WASHER MAKING LOUD RATTLIN NOISE ON SPIN AND BELT CAME OFF!?

Hi my Servis washer has been making a really loud rattling noise and heavy vibration when on spin for the past few times then yesterday it stopped working altogether.I have just had the back off and noticed the drive belt had come off, so I put i back on but when the drum turns it keeps slipping to the back edge.Whilst the belt was back on I turned it on again but it still makes the loud noise and looks like its going to take off.
I would really be grateful for any advice as I'm a single mum and and really can't afford a new machine.Thanks