Company is asking to pay 150000 as other deduction in the FnF

I have join a company in and signed a agreement of that if i leave the company before 6 month i have to pay 75000, 6-12 if have to pay 100000 and for 12-18 is have to pay 150000. the amount is increase till 2 years/ The amount has mentioned as the company should recover as training expenses. however they did not give any kind of training, they just provided a already downloaded Udemy course to watch and some times a senior comes and ask about the progress, other then that they did not provide any kind of training or certification. I did resigned from the company in the 17th month i was not able to serve my notice period due to some reasons for that i am paying lieu of the salary for remaining period of notice. My request was approve and received my Last working day from the company and after submitting company laptop, I did receive my resignation mail from the company and they said it will take 45 day to proceed with my fnf, so after 45 I contact the company for the FnF. Now they added the 150000 in the FnF marked as "Other Deductions". I asked them to explain that what are the other deductions are for and they are not replaying with any valid response just sending the same email template again and again. What should i do, I can not pay that amount as my salary was very low and can not afford that amount. There are multiple cases they terminate some of the employee by forcing them to resign on immediate basis and did not let them serve notice period or asked for that amount. If i did not pay the amount they will not give me my relieving letter/experience letter. The experience letter is very important for me for the future.