Working at enterprise car rental company. I feel I am not treated right.?

I am a service agent 20 years old i clean cars. well they told me I am a temp not witch i did not understand because the group that had got hired with me are all permanent and they said because of that i will get paid differently (less) and it is a list called a sincerely list. basically people who worked their for years choose their schedule fist then the people who were just hired i was hired before this girl at work and im on top of her she went off cause she wanted my work days they say because im a temp she can bump me and take my days. so unfair and she didn't come for 2 days. missed work and calls out .. this job stress me out always messes my pay check up and i work 40 hours. if you worked here was your experience like mine. if you didn't how does this sound to you