Latitude Fintech Full Stack Developer interview questions

I apply for job through HackerEarth challenge. after shortlisted from challenge I had an Technical Skype interview where I have to explain the complete project which I make in HackerEarth challenge. It was nice interview experience.I clear the technical interview then I had Telephonic conversation with HR . Its not like an HR interview it was just a telephonic conversation.she explain me the role , and had salary discussion.Salary don't match with my expectation so I reject the offer. then next day I again get call from HR for salary negotiation and this time I accept job offer after some negotiation from both side. And she told me that she will mail me offer letter.I wait for 4-5 days but I don't get any mail from them. so I call them but no one pick the call then I email to HR but I don't get reply. almost 10-12 days pass. I again call HR to ask status.after many calls I got call from her, she told me that they don't have vacancy right now for that job.