Recovery suit and defamation

1. In case of the forest department of Himachal Pradesh, invited tenders for the sale of timber 2. Arun and Karan filed application for the same. Karan approached Arun and convinced him to enter into an agreement in presence of two persons whereby Arun’s tender shall be quoted for higher amount than Karan 3. In consideration for not competing with Karan, he gave a post dated cheque to Arun for Rs.15,000 signed by him. 4. It was agreed that if Karan’s tender gets accepted Arun will get the money from Karan. His tender was accepted but he gave instructions to the bank to stop the payment of the cheque to Arun 5. Arun filed a suit to recover the amount of the cheque 6. Karan pleaded that he had not entered into any such contract with him. Rather he counter claimed before the court that the same has led to his defamation and claimed compensation of Rs. 50,000 Issues: 1. Whether the agreements between the parties is valid or not? 2. Whether there is any defamation on the side plaintiff or not? please held especially for the 2nd issue