Sirius/XM Radio Fraudulent Sales Tax Collections Washington District of Columbia

On reviewing my billing statement, I noticed that the company is collecting 5% city sales tax and 8% state sales tax.  My city (Titusville) has no sales tax, and my state's (Florida) sales tax is 6%.  I addressed this with the company via "chat", and was told to research my sales taxes myself.  I called customer service, and was told their computers automatically apply tax rates to the bills, and that's that.  I'm still trying to cancel the subscriptions on my three cars, and that's not going to well either...I wonder (no I don't, really; I know) for whom they are collecting these fradulent taxes, and why no one has noticed or succeeding anything about it?