If you are in NC, then it is likely that NC laws apply, not those of WA.
You should find the government office in NC that handles wage law complaints. In WA, that department is the WA Labor & Industries. The office in NC may have something with a similar name.
Whether a person is contractor or an employee is determined by the law. An employer and an employee cannot agree to make an employee into a contractor.
How much control an employer has over an employee's work is a major factor in whether the person is an employee.
What you describe seems to make you an employee.
Besides the government office, you can review the specific facts with attorneys in NC.
You really need to consult with an employment attorney. The agreements you signed may or may not state what state's law apply to which agreement. Nonetheless, as you are working in North Carolina, that state's hour and wage laws would apply and from what I understand are not nearly so protective of worker's rights as Washington. Document everything as it happens and then take that information to a local attorney who can advise you as to whether or nor you have a cause of action.
You and your co-workers may have a claim. You should seek out an attorney that specializes in employment law to review your circumstances. Someone in my firm would be happy to discuss it with you.