I'm sorry to say that because they are not a medical provider, they are not bound by the medical privacy laws to which a nurse or doctor would be bound. As a result, you invited them into your home for work on the Internet, as long as they are telling the truth and not defaming you, such actions are not illegal. Now, I would report them to their employer and explain how unprofessional and how much trouble they have caused you. That is really your only option.
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Probably no grounds for a lawsuit here. Reporting the conduct to the installation company and the internet provider might get you something like free service or upgrades.
I suggest complaining to the company. I do not see a basis for a successful lawsuit. I suspect their privacy clause is written to apply to your content, movies and such. You could consult an attorney and provide more detail.
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