In such cases you have two options one is approaching Labor Commissioner and second is approaching Civil Court.
If the previous employer mislead you, then yes you do have a case. But you have to prove it. Generally employment agreements include a restraint of trade clause to protect their own interests. To be enforceable, employer must prove the clause is reasonable. As per the Bonded Labour System (Abolition) Act, 1976 no employee is allowed to work for a particular tenure in a company out of compulsion. Such agreements cannot be legally enforced. In order for an employment bond to be enforceable, it has to be executed on stamp paper. Also, under section 27 of the Indian Contract Act, 1872 no employer is permitted to include a restriction, directly or indirectly forcing the employee to work for the employer. Please mail me a a copy of the letter. I will into the terms and conditions and give you an opinion. Do get in touch with me for any further details. Looking forward to your response.