Okay, first things first. Was it an insurance job, or private. If it was a private job, then how much did they charge. Did they charge the cost of a complete skim, and just patch it. And did they warn you of the way it's look afterwards, or was it case, of fine, you'll never notice the repair.
They would have needed to break of the stipples surrounding the join, and then tape and skim the area, then they attempt to restipple the area, but it would always look "redone".
If it was an insurance job, then they should have broken the top of the stipples off, and then skimmed the whole ceiling, and then restipelled it; or they could have put bonding over the stipples, and then skimmed it.