Question about the Bond in I.T. companies

I have joined in a I.T. company on January 29th, 2020. At the time of joining they have given a condition that I have to sign a bond for two years and they have also asked me to submit the class 10th admit card and 12th mark sheet. I have started to work there with a 6000 rupees stripen per month and it was also stated in the appointment letter that they will increase the amount at the time of confirmation of my job and that will be within 3-6 month(They have not created my P.F account on my joining as they said they will create the P.F. account once the salary will get increased). I got the confirmation letter by July 2020 and then also they have not done any increament in my salary on that time. They did the increament on the month of November 2020 and they increased the salary to 12000/- per month but never spoke a single word about P.F. In March, 2021 they finally asked me to create the P.F. account (after 1 year 2 months) and when I got the salary slip for the first time in the March, 2021, I saw that the DOJ (Date Of Joining) is written March,2021 that means from the month they have started to decuct the P.F. amount. It's the month of July,2021 almost and I have spent 1 year 6 moths already with that company. But earlier this month when I got a job in another company, they have refused to release me and said that you'll not get back your documents as you have signed the bond of 2 years bond. I will be thankful if anyone provide any solution for that and also how can I get back my documents from there?