FnF not done

Dear Sir/ Madam, I was placed in Jaro Education after completion of my MBA. I had served the organization for 18 months with full commitments and loyalty. I had communicated my wish to resign from the job to my reporting manager in the month of January 2015. My job was of business development executive and we were given targets every month. After having a long conversation my reporting manager concluded that i am demotivated and under pressure .He asked me to take some day leave and think about it.This happened again after two months. In the month of May finally i droped my reporting manager a mail saying that i wont be able to continue and so i will be serving my one month notice period starting from 19th may, 2015. Being a sales organisation we had some target based competition going on so my reporting manager dint responded to the mailer. Later after 7 days i asked him about the mail which i had sent him to which he said i will talk to you later and left for the day. Next day again i asked him and he explained that in sales based organization up and down are part of one's career.h He see a great potential in me and dont want to loose me so i should take a break of some days and join with enthusiasm. I responded by asking 10 days leave to think about it which he granted immediately. On 1st July,2015 i finally wrote him my resignation letter saying that i wont be able to continue from next day onward and consider this as my last working day. He asked me to report to the HR immediately. I HR confirmed me that after 45 days my pending incentives and last month salary will be given. After 50 days , when i dint heard anything from the organization , i contacted the hr. Later after two days i received a call from the head office that i should pay 10k to the organization in order to get my FnF. As of now i have written n no. of mails to my reporting manager, the hr and head of organization by in vain. I understand the norm of notice period.In our case it was of 1 month.I want to ask here that if my reporting manager was aware of my conditions that i am not willing to work any more from last 6 months or even my notice period mail , on what grounds they have blocked my FnF?