1. You have no evidence that you had paid Rs.3 lakhs to your friend to file a case against him,
2. Now, since he has agreed to issue you the said cheque, accept it immediately with a covering letter wherein he will admit having collected the said payment from you for the said deal and also an instruction to deposit the cheque if the deal does not fall through with in 31.10.2014,
3. By this you will have his admission of having collected the payment and also kliability to repay you,
4. In the event his said cheque bounces, you can file a case u/s138 of N.I. Act against him.