I heard a BBC interview with the head of whatever organization they worked for. He stated repeatedly that they had been negotiating "diplomatically" for the release of their people, and that he was "very happy" that they were now safe. When asked if they were aware that there was going to be a rescue, he said, "We knew something like that might occur, but we had absolutely nothing to do with it".
Throughout the several-minute interview there was not one phrase, nor even one word that implied any gratitude.