Denial of maternity benefits

Hi,
My wife had worked with a local IT firm in Ahmedabad for 2 years. She was pregnant and delivered in Sep'10. Earlier she was denied maternity benefit by her company but later on they agreed verbally to pay her for 3 months of maternity leave. However, she did not get salary for first month of her maternity leave. Upon inquiring with her HR, she got to know that she will get salary only if she joins back. She resumed the job on 01-Dec. However her company told her that she will get the salary for her maternity leave of three months only if she continues with the company for 12 months and that too in 12 installments. Because of this unfair treatment she resigned from her company with last date as 25-Dec.
When she mentioned Maternity Benefit act 1961 to her HR, they responded saying they are not liable to pay and they have consulted their lawyer.

I want to know can any private company deny salary for the maternity leave ? In this case as it had happened whom should we approach ? I had gone through the Maternity Benefit act 1961 and it says that the employer is bound to be jailed for 3 months if he/she refuses to provide maternity benefits to their employees.