Questions d'entretien chez Conversion Bug

I got contacted by a recruiter through LinkedIn. There are four rounds of interviews. First one is written test or online test. Second: Group Discussion. Third: Technical Interview. (based on past experience and skills) Fourth: HR. The interview went seemingly smoothly.

There is a small interview process and I entered into this company with my friend's reference and I signed offer letter with one commitment there is no bond but I didn't felt comfortable So I quitted my job in 2 months but an end of the month they decline to give me my salary.