Receiving back pay

When I was hired my employer promised me $8 an hour and that is what everyone else in my department hired at the same time and after me is making. I did not notice right away they were under paying me and when I did immediately asked for the rate to be changed. After several months it came to my attention that the rate had either never been changed or reduced back to my original rate. I have now fixed the pay rate to $8 where it should be. I also asked for the back pay for the months since I was first told the issue would be corrected. While I do realize it is my responsibility as the employee to ensure this was done I just wanted to know if I did have any legal footing in the case my employer denies the back pay I have requested.