Service Bind

I got placed in an organisation with 3 years bond and a sum of 4 lakh has to be paid if bond if broken. However on joining we were given training. And for training we were just allowed to roam any where in plant. And 1 person of that dept. Would take 30 min and explain about the departments. This continued for 2 months. After getting my department I realized the harsh Conditions in the company. I found out that the tools and softwares that we were using, no training was given to us. And they told us it on job training. Now they started giving pressure to us knowing that we don't know the work. And there is no one to ask also if someone gets stuck. They were calling us in shifts, sometimes morning, sometimes night without any shift allowance. They didn't have enough systems for all the employees. And at times we used to wait for our turn. More people less systems. Even the systems were not configured as per requirements of the softwares being used. Thus it made the work even worse thus people end up staying for upto 18 hrs in office. I also stayed up to 15 hrs in office of which there is no overtime payment. One guy once stayed in office for 2 days. Even Saturday and Sunday they call there employees without payment. This was very disappointing as we were learning nothing. We asked for training but they keep on bouncing the topics. When they got work they scolded us like anything. But then they won't provide proper systems to work too. I left the the organisation after telling my HOD. and send them a resignation letter. Now they sent a notice of absence from duty. They told to come back to office otherwise they will take legal actions. I know I signed the bond. But I can tell that they didn't spend more than 5000 on us.for example a course on solid works is worth 20 000 outside but they didn't provide us any training. How one can deal with such bonds. Please explain. Also last year many guys left the organisation and some with bonds also. One guy replied through lawyer and didn't took any action. With me one more guy left. What to do in this situation