Arena Capital interview questions

There was no formal interview invite via mail, only a telephone call. When I reached the venue at the allotted time, there were about 7-8 other candidates there, and all of us were taken in for a group discussion sort of a thing, rather than one-on-one interviews. After this, almost all of us received invites for the next round, which was kind of like a written test. And then, they called us in for another round in which they made us work an entire day (no compensation). The work was for an existing client, so I feel like the interview conducted was more like a scam, rather than an actual employment opportunity. I know that a few days after this, they posted the job again, and again after a couple more weeks. So, it seems like the company does 'mock' interviews just to get young and desperate candidates to work for them for free. Will take this like a bad experience and never again do a full day's worth of work without being compensated for it.