surety bond

My company forced me to sign the following surety bond:

I hereby undertake on this_____day of _______________, 2015/16, that I, Mr_________________________ S/o Mr._________________________ CNIC No__________________________ resident of __________________________________________________________, presently employed as _______________________________with Fauji Fertilizer Bin Qasim Limited at Head Office, Islamabad , to indemnify Fauji Fertilizer Bin Qasim Limited against all expenses (Stipend, Bonuses etc) incurred on my apprenticeship training, if I leave the service of the company before completion of apprenticeship training and after regular hiring, as given below:-
(a) During apprenticeship training, I shall pay full expenditures incurred on my training.
(b) In case of regular hiring after completion of apprenticeship training, four years’ service will be mandatory. If resigned during this period, I am bound to pay following amounts to the Company:-
1) Before Completion of one year service – Rs. 400,000/-
2) After Completion of one year service – Rs. 300,000/-
3) After Completion of two years service – Rs. 200,000/-
4) After Completion of three years service – Rs. 100,000/-
5) After Completion of four years service – NIL

Date: _______________ Signature: _____________________
Place: _______________ Name:________________________
P No:_________________________
CNIC No:_____________________
Address:______________________
_____________________________
Witnesses:
1._____________________________
______________________________

2._____________________________
_______________________________
ATTESTATION OF CLASS-1 MAGISTRATE

I have resigned recently in order to pursue higher education and my company now has not given me my last 2 month’s paycheck and security. More over they’re telling me to return all the salaries they have given me, even though I was forced to work for more than 10 hours 5 (often 6) days a week. Isn’t this illegal, as in like bonded labor? Also if I do not return my salaries (which was my right), what can they do about it?