How to secure refunable deposit with franchisor

Dear Sir I am channel partner ( similar to franchise ) of NEET / JEE for certain branded Educational Company . For this purpose , we had signed MoU ( not registered ) in the month of 24 Aug 2015 . The term of MoU is one year . It required Rs 500000 refundable deposit , which bears no interest. Instead I asked with them , to give the following and accepted . 1. Post dated signed cheque , quoting 31.05.2016 for Rs 500000 ( as academic year ends and we might complete crash course during May ) 2. Signed Promissory note ( blank ) Accordingly we agreed and entered into contract by paying and exchanging documents . In that year , my net lose is Rs 2.5 lacs . Though , I hoped the business to do well in the second year and thus renew the MoU , both signed at the back of old MoU , noting that the terms extended to another one year . I surrender the post dated cheque and received another post dated cheque , wide dated 31.05.2017. Then at the year end , my accumulated loss is 4.5 lacs . As the government announced that NEET becomes mandatory to hold medical seats in the year 2017-18 , I renewed MoU with a new rays of hope . For this time , the previous year MoU papers were cancelled & had been surrendered to Head quarter and carried out a new MoU with few additions and omissions . Cheque was exchanged for the date 31.05.2018. But for this time , they asked me to surrender promissory note . They said that it has been asked according to the Auditors direction . I fear to the following points . 1 . When other two channel partners asked to refunded deposit , telling their wish to terminate the MoU , he refused to refund he same 2 He refused by other means that he showed some disfigures in accounts as outstanding from channel partner side . 3. I wish to be safe on my side . Kindly advise