"I was NOT informed that "taxes" not included in the initial debit to my new order would be added to my account and debited after the installation. Only when I contacted customer support about what I perceived to be an unauthorized debit from my bank account was I informed of this dubious practice."
There's nothing dubious about collecting taxes.
Did you not do any research on the company's website regarding how the service works? Do you usually just expect others to do your homework for you? A lot of what you are complaining about could have been easily avoided if you had actually researched the service.
You may want to request a review of your sales call (if it is still available, the company can pull it up and have it transcribed, so they can see what the sales person told you and what you replied to them).