Employment bond related quiry

Hii, i was recruited by a company in my final year of b.tech where i have signed a bond of 3 years amounted 5 lakh with them which is not applicable in case of higher studies or government job. 1. After few months there starts some salary delay issue, also they haven't provided any bonus in between pf submission from there side also strtd getting delayed. So i decided to quit the company. 2. I took admission in a AICTE approved college and put my resignation on behalf of that. In between this i got a offer from another company. 3. Now i have served their notice period on their full conditions, completed my task by serving even on Saturday and sundays for 2 months and 25 days. After that i was relieved from there and i joined new company. 4. After my joining at new place they come to know about it and now they are claiming 5 lakh from me.even my 1 month and 25 days salary is also due on them and my 6 months pf is also not submitted in my pf account. What should i do in this case, please help.