Bond validity in India

Hi Sir(s) I joined a construction company during in August 2016. I got the vompany through campus placements. I was offered a CTC of 6 Lacs per annum. But there was a bond for 5 years which if broken I needed to pay 15lacs , which they said would account for all the expensesof training including a 6 month training in Singapore. Now, after 7 months of work in this company, I wish to leave this company and persue higher education. I have already talked to the HR and have agreed to relieve me but on the condition that I should be paying 4 lacs. In this 7 months of mine, I was in our corporate office studying the processes of the company and after which I was transferred to site. Now this 4 lacs which they brought up was considering my entire 7 months in this company (including my 5 months at site). At site, I worked as a normal employee. I never got to feel that I was undergoing training. I had tasks to complete on a daily, weekly & monthly basis. I was corrected by my boss (rudely as well as politely) whenever needed. Like I said, I never felt I was undergoing any training. I felt like I was working. On an avereage I worked for about 12 hours a day.Now after gojng through so much trouble, is it right of them to ask 4 lacs for me to be relieved. Awaiting your kind perusal