Salary not credited and done cheat on me by false statement.

Dear Sir/ Madam, I was working with an startup company, suddenly a company HR person called me for interview with their client location and it was an urgent requirement. I shortlisted in the interview and they asked me to join immediate from tomorrow or day after tomorrow. Also they agreed with my expected salary. As it is very short notice for leave my current job, as their salary offered is fulfill my expectation, and Offer letter will be release and share with me with in one or two days, because of their some internal procedure. so that i decided for quite current company and go with them. After one day expand with their client office, they had not provided me even joining letter nor offer letter as well. Now they start playing with me that we will provide the same today/ tomorrow. And after completion of 9 days expand in their client site, they told me that we will keep as backup resource. and will provide me the salary which expand there in the client site. Till not they have not provided me any job offer nor given my salary which i expend over there. They were fully played with me as i quite my earlier job due to their false commitment. After so many follow up, they are not answering me nor replying. I was demanding for one month full salary or an onsite employment. But they don't any thing. Kindly suggest. Thanks