I sent my first small quilt out to be quilted by a LA. When I went to handstitch binding, I caught my needle on a 1/2 inch unstitched area which repeated a few times along the same horizontal line. What can be done?

If this is in the binding area, she was tacking your top down, which should be on the inside of the binding and not showing on the quilt.
should be fine.

If it is the tacking stitches you can pull them out with no problem. I pull mine out before returning a quilt but sometimes you miss a few.

I don't think it should be a problem.
If we are misunderstanding your question, can you post a picture of this? :D:D:D