please do help me with the questions.... The commercial law of Malaysia (law of agency)

Aina who had migrated to New Zealand, had appointed Donald to be her agent. Aina told Donald to sell her bungalow in Damansara for a price not less than RM 2 million. Aina also owns five other properties in Klang Valley which have been rented out Donald was to collect the monthly rentals and keep proper accounts. Later, Donald informed Aina that he could not sell the bungalow at that price. Instead a potential buver interested to purchase the property at RM 1.5 million. Aina agreed to his suggested and authorized the transaction for the said bungalow. Five months later, Aina returned to Malaysia for a holiday. She discovered that the buyer of the bungalow is Donald's wife. Siew Ling. She also realized that the collection and recording of the monthly rental were not in order. After full inspection, Aina discovered that the collection was in shortage of RM 150,000. Aina was very upset and she wishes to know whether Donald has breached his duties as her agent Advise Aina for remedies that she can seek against Donald (25 marks)