Not getting paid for working interview…

A little background: I live in Texas and I applied for a job and got a working interview, wasn’t sure the job they made it out to be, so I’m not working there, but put 3 hours in of scrubbing cages, cleaning up dog shit, etc. I’m getting told that I will not get paid for my working interview. Is this legal? Again, it wasn’t just simple paperwork, I put in genuine hard labor.