i have crossed the interview of amiga informatics for us it recruiter postion. and i got the offer later by the company. but when i goes to joining then they said to me. you are not eligible..if i am not eligible ,why i am selected..company management is unprofessional .. and i think comapny is frode

I have crossed the interview and got offer letter after 7 days company hr says u are not suitable for our company not me includes 15 peoples not suitable for her company.highly unprofessional peoples. They doesn't know anything please suggest what should I do such fraud peoples. Fraud fraud fraud..,.