draining work and uneven workloads among workers and not enough pay - Sales Associate Old Navy Employee Review

So I was a full-time student working part-time at old navy. They made me work 39 hours a week even when I told them that was too much. I was made to work more demanding hours (evenings and weekends) and was the go-to employee whenever customers needed anything. Other co-workers would sit on their phone on the floor while I was expected to do all the work. Maybe I'm just too nice, but IDK. I would complain, and management would say they would speak to other employees about their poor work ethic but never did. Honestly, I should have been paid a manager salary, for I did just as much as they did, sometimes even more. $10 at the time seemed amazing pay for my coworkers who weren't even asked to do anything, but for me, it definitely wasn't enough. I even reached out to the district manager, who constantly promised me he would try to fix the issues going on at our store, but he never did. also, the store was also a mess, and it was embarrassing to work there. Anyways I guess it's a good job for 16 year olds, but definitely don't work for more than a year.