Bank forcing/mentally torturing me to pay the service bond

Respected sir, I have worked for less than 3 months(including notice period month) in a private bank and i have completed my notice period(1 month) as well & bank didn’t spend any money on my training. I was recruited under a diploma course from manipal in which i have paid money(rs 4,13,000) to manipal, not to the bank. They took a service bond from us which was signed at the time of starting of the course(we weren’t given appointment letter at that time they just gave letter of admission to manipal) appointment letter was given after 1year on completing the course. After completing the course they didn’t take any bond from us, in bond it is written that if the obligor chooses to discontinue the course and/or resign from the services of the bank or leave/abandon/ discontinue or quit the services of the bank by giving requisite notice, before the completion of the bond period of 3 years, such act of giving notice shall be deemed to be a trigger for the bank to invoke these presents and the aforesaid sum of rs 2 lakh shall become due & payable forthwith. The bank didn’t ask any candidate to pay bond money who left the course in between. Isn’t the bank violating their own terms of taking bond amount who leaves the course. And i have heard that the bond should be signed/made between the duration of appointment letter & joining date. I talked to HR they said that i have to pay bond otherwise i will face problem if i join any other organisation. What should i do I don’t want their experience letter of 2 months it’s no use for me. I just need the relieving letter. I don’t want to pay bond amount as i already have spent 4,13,000 on the course