What you described does not sound anything like an independent contractor position. As an IC you are only responsible to your client and you would dictate your own hours.
If you are told when to come to work, what to do, you work on another's premise using their tools and equipment, etc I would say that you would likely be considered an employee under both state DOL and IRS guidelines.
Further, if you work for the PDAs then only the PDAs can terminate you. That is, you need to work out a schedule with them directly and if others interfere this should not prevent you from coming to work on schedule and billing your client accordingly. You ay also have an independent claim against these other providers if they are interfering with or frustrating your contract with your client.
You may want to discuss in more detail with a lawyer in private. Most of us here, including myself, offer a free phone consult.
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