Hi
1) In your case, since you have not been issued even an offer letter, you are a temporary / contract employee and hence your employment (inspite of no offer letter) is governed by Indian contract act and host of other labour laws.
2) Payment of wages act will be the law governing your employer. Under section 5 (1) of payment of wages act, salaries should be paid to both employees and contractors before the expiry of the seventh day,after the last day of the wage-period in respect of which the wages are payable:
3) In case your employer has not paid salaries , then he has violated both the indian contract act as well as payment of wages act.
4) You should issue notices to employer demanding the
a) payment of salaries and
b) return of academic certificates and
c) Issue of service certificate and relieving letter.
.
5) if your employer does not pay the salaries and return the academic certificate inspite of the notices, please note that you have the right to pursue
a) A criminal complaint with the police for not paying salaries and with holding your academic certificate and /or
(please remember your employer has not issued any offer letter to you and also that he is withholding your academic certificate which is a criminal offence.
b) file a complaint with the Labour department on the grounds of non issue of offer letter, non payment of salaries and withholding certificates inspite of you working for the company. SInce your employer has violated all of the known labour laws, his office premises will be sealed by labour department and personal properties of employer will be attached. So No employer will risk the labour department.
Hope this information is useful