Can't see the axle in your photos. It was just a guess based on some previous threads where similar problems arose and that was the problem.
Was the axle ever taken out? If not then I'm off base.
If it was taken off then proceed to the next step. (If it fit before it went to the shop, and now it doesn't there just isn't much that could have changed).
The butt end of the axle goes up to the speedo drive. The speedo drive should be nestled into its drive plate and turning freely. The spacer fits into the oil seal on the side of the hub opposite the speedo drive. And this is important: the nut goes on last with the hex portion TOWARDS the hub.
If all this is correct, then I'm out. Good luck.