Thank you for the information and your question. Although the employer can pay vacation and sick leave at a reduced rate, as long as it is not below minimum wage
, they must post the change in policy with the amount of the pay before
they can effect that change with the employees. So, since you say your employer failed to post the amount of pay for vacation periods, you have a couple of options. One is to file a wage claim with the State and the other is to file suit in small claims court for the difference between your hourly rate and what you were paid. You can ask the court to award you double what you are owed since this is a wage issue and also for your court costs and any reasonable attorney's fees you might have.
I will tell you that you might want to try to wage claim first, since it is easier. However, the State may not take the claim since this has to do with vacation, which is a fringe benefit and not required to be offered. But, it would be worth trying first, before you have to file suit.
You can find out how to file a wage claim by going to: http://www.in.gov/dol/2345.htm#108
Please let me know if you need any clarification. I would be glad to assist you further if I can.