Mr. Didi is the owner of Rich Development, a developer company. He appointed Mr. Jojo by express appointment as his agent to find a suitable land for his latest housing development project. It was agreed between the parties that Mr. Didi will pay RM10,000 to Mr. Jojo as commission upon completion of the transaction. Later on, Mr. Jojo met Miss Nana who owned a piece of land at Kuala Selangor. Mr. Jojo entered into a contract with Miss Nana on behalf of Mr. Didi to purchase the land with the price of RM800,000. Recently, Mr. Didi found out that the market price for a piece of land around that area is just RM600,000. He also found out that Mr. Jojo had received secret commission amounted to RM50,000 from Miss Nana while negotiating the contract on his behalf. As a result, Mr. Didi suffered a loss. Explain to Mr. Didi as to his rights and duties arising from his contract with Mr. Jojo. In the course of your answer, advise Mr. Didi whether he can sue Mr. Jojo for a breach of contract. Support your answer with Contracts Act 1950 and decided cases (if any). (10 marks)