Hi
1) Since your employer has defaulted on payment of salaries on the stipulated date, he is primarily responsible for breach of contract if any.
2) Also since there is no mention of Notice period in your offer letter, it is deemed that it is an "At-Will" employment and both the parties(employee and employer) can severe their obligations as per their own will.
3) Also given that you are yet to complete 1 year of service and also given that your employer has not confirmed your employment, you are still deemed to be a temporary worker and hence both sides can severe their obligations at WILL.
4) With reference to you sending the resignation letter, you did the right thing by sending resignation letter to your manager through Mail.
5) After receipt of resignation letter, an employer cannot terminate the employment of the employee.
6) The employer is bound to relieve the employee from the services of employment on the basis of resignation letter and not otherwise.
7) A person is deemed to be an employee of the company till such time the employer formally relieves him from service
8) Unless stipulated in your offer letter or employment letter there is no requirement as such of notice period.
9) All IT companies in Gujarat are bound by rules of shops and establishment act and labour department rules.
10) Since all of the IT Companies are empowered to self certify their monthly and quarterly returns, labour department does not visit them or raid them unlike other industries. But that does that mean that an IT company can circumvent the law or act arbitrarily .
11)You can still choose to complain to the Labour department in case of non addressal of your grievance.