Employees are granted many rights when they are hired by a company. It may feel as though your employer is this monolithic behemoth that has all of the power in the employment relationship, but this simply isn't true. They have many rules, laws and regulations that they must follow, and they can't treat you unfairly just because they are a big player in the industry.
Employees are granted protection from discrimination in its many forms; they are free from harassment of any kind; they are protected against retaliatory actions by their employer; and they also have the right to fair pay and wages for the time they have worked.
In relation to that last point: sometimes employers will not pay their employees for the time they worked, either by accident or on purpose. Maybe the company is poor at tracking their payroll or keeping financial records. Maybe there was a glitch during payroll processing. Or maybe, they didn't pay their employees what they were owed in an intentional and malicious effort.
No matter the case, these are unacceptable circumstances that employees need to address as soon as possible. If you are not being paid what you are owed -- may it be your usual wages or overtime wages -- then you should consult with an attorney as soon as possible. There is no reasonable excuse for a company to simply not pay an employee what he or she is rightfully owed.
Source: FindLaw, "Employee Rights 101," Accessed Dec. 2, 2016