indesit DI620 top rotator not spinning?

I recently cleared a blockage in my dishwasher using unblocker and bleach. I have now noticed that the top rotator is not spinning yet water jets through it no problem. i have cleaned all the holes in the top arm and water jets through them inside the dishwasher but it still does not spin around therfore leaving cups dirty on the top rack. I did find a piece of rubber in the bottom of the dishwasher a few weeks ago and can describe it as 2 rubber push on caps around 15mm diameter linked with a flat piece of rubber, one cap slightly larger than the other. i am not sure if this is even from the dishwasher and if it is does it somehow go on the back of the upper say arm connector as it meets the hole in the back of the dishwasher. either way im very confused and cannot get a di620 schematic anywhere on the net. any help would be appreciated