Employment bonds are employment agreements with negative covenant. Under the Indian Law, the employment agreements with negative covenants is valid and legally enforceable if the parties agree with their free consent i.e. without fraud, coercion, undue influence, mistake and misrepresentation.
The employment agreement is required to be printed on stamp paper which is to be signed by both the employer and the employee and shall keep a copy of the same for their own records. So, in your case as the bond did not have a stamp paper then the bond is not valid. Hence, you were not liable to work for one month. You can file a case of cheating against the employer under Section 420 of the Indian Penal Code,1860.
If your employer is not paying your dues for the work done then you can send him a legal notice to him asking him to clear your dues and if he refuse then you can approach the labour commissioner and file a complaint to him.
If still your problem is not solved then you can file a suit under Section 33(c) of Industrial Dispute Act, 1947 recovery of money due from an employer. If your salary is less than 18000 you can file a case in the labour court for salary exceeding than 18000 you must file a suit in the civil court.
Reference: Section 420 of the Indian Penal Code,1860.
Section 33(c) of Industrial Dispute Act, 1947