Complex sentence: When Hanno refused their demands, and tried to explain the Carthaginian point of view as Carthage actually hoped to reduce the payment amount, and mercenaries were unsympathetic about the financial difficulties of Carthage, and the negotiations broke down.
Split into simpler sentences: When Hanno refused their demands and tried to explain the Carthaginian point of view as Carthage actually hoped to reduce the payment amount. The mercenaries were unsympathetic about the financial difficulties of Carthage and the negotiations broke down.