if you did the work, I would have to say you're entitled to the money you agreed on.. It wouldn't be much different then having someone come into your house to paint, and they paint 2 of 10 rooms and you say you don't want them to do it any more.. You would still have to pay them for their work done.. If not the full amount agree'd on.
On a side note.. I'll leave this up (i know both parties in this situation) but if names get mentioned or it becomes a BOI issue, which it;s borderlining on now, it will have to be removed.. IM sure you understand though David..