travel company to avoid

My wife and i booked a 10 day tour of Argentina from one of the reputedly largest south american tour companies which specialize in such tours. Half way into the tour we were left stranded in the tiny airport of el calafate, argentina ( small town in patagonia)because our tour company did not pay the local tour operators or hotels for the rest of our trip. Despite constant phone calls to the travel agent and company daily we were left to find a way home by ourselves and spent a lot of money doing so. despite this ruining a lifelong awaited trip and the travel company's agent telling us in his emails that this had never happened to his company before and assurances we would be helped, we were not and they have refused any compensation for the tour parts not done or for any of our expenses getting home. American express was even unable to budge them despite 3 months of trying.