Take Over of a proprietor Firm

Sir, Myself Ramu. I took over an proprietorship firm from one of my Family Friends (name 'X') in jan'2013 and mutually agreed to pay 10Lakhs as of goodwill to 'Mr.X' and agreed to be responsible for the firms debts. i paid him some advance and cleared off all debts at the time of agreement and rest to be paid in 3 months. If i fail, he agreed to return the adv and all the money i have invested on the firm retaining 1Lakh. Unfortunately Mr.X went abroad in the next month. With belief on him i didnt make any agreement with him. Even after coming to ind after 6 months, he was well and good.Basing on our relationship, i agreed Mr.X to work for the firm on salary and the money im supposed to pay him would be paid whenever he needs(as Mr.X said). After a certain period of 8 months, i paid him all the 10L as agreed and used to pay salary. we used to run the firm on mutual understanding without any ownership transfer for some period. At some point, when i asked Mr.X for further proceedings, he said that i didnt pay him all the money and also he says that the agreement dt. jan'2013 is not valid now. I felt this is my life and invested a lot of mny to run the firm. For my question to return my money as per the accounts stated, he doesnt agree with my accounts, the mny i paid him and mny that i have invested. At this juncture, how can i proceed? All that i have is an agreement dated jan'2013, some blank cheques signed by him, and empty letter heads signed by him. Kindly treat this on priority and give me the best suggestion to come out of this problem.