Drum seized ?

I had the F11 fault come up, and I have found the drum to be seized, can't turn it left or right. The engineer locked the two drums a while ago as it was tearing the cloths. I use the washer only for dog blankets etc now, but it is so good for this, I would like to get it going again. The motors both work but the belt get forced round the stuck drum. Any idea how I can free this.

Ian