Niksoft Systems interview questions

Did 4 phone interviews. Wanted to know about my work experience but very few questions were asked. I was offered the position, signed an offer letter and then the company stopped contacting me/responding to emails. Eventually I was sent a generic email thanking me for taking the time to be interviewed but they decided to go with another candidate. Very unprofessional considering I signed an offer letter, was dropped, and now the job is posted again. Very unprofessional company, thankfully I found something better.