Ask HN: Company not paying salary on time, what to do?

It's been 2 months since i joined a local startup. I joined the company at the end of January. For the first month, i got my salary during the very start of march, that too on forcibly mailing and chatting with the company. Now, for the second month it was delayed for 17 days before i got the salary. As an employee, i would want to quit the company based on these problems and would like to quit as soon as possible without serving notice period. Now, i'm being threatened from the employer saying he can sue me for not serving my notice period. It states in the offer letter that, "Your services shall be terminable by either party giving the other two months’ notice. Company may, however, reduce this notice period at its discretion by accepting basic salary in lieu thereof." So, based on the statement the company can take the salary for the current month and relieve me, if i'm not wrong. However, offer letter sent was sent to me as a soft copy to my mail during the start, nothing practically signed. Even at that point, to get the offer letter from the company, i had to mail them constantly to get one. So, the Director of the company is using abusive words on me and threatening me for my relieving. Just wanted to know, What are the legal protection i can get?