My understanding (correct me if I’m wrong) of the economy of this business is that of the price you pay, part goes to the manufacturer, and part goes to the provider for the setup, tuning, and service.
You may have exceeded your provider’s “desired” level of service, but they are probably under certain obligations from the manufacturer.
What I would do is start with the manufacturer. Tell them who your provider is, what they’re refusing now, and ask the mfgr if this is appropriate. If it isn’t ask them what you can do. Maybe they will light a fire under your provider, or at least suggest what recourse you have.
If the mfgr says the provider is obligated but can’t help you from their end, go to your state’s Attorney General’s web site and file a complaint. Rather than just make it breach of contract which you would have to pursue in small claims court, assert that it’s theft of service or fraud. You can try to claim they’re defrauding you by misrepresenting their obligations to provide service.
File the complaint, get a copy of it, and send it to the provider. If you know a lawyer who will attach their letterhead to it with a note that you’ll withdraw the complaint if they honor the service obligations, it will go a lot further.
Just a couple of ideas. But start with seeing what the mfgr says about the situation.