If you have medicare advantage plan do you pay the insurance company, the $104/MONTH TO GOV, or both?

You pay Medicare the $105 per month PLUS you pay whatever the Advantage plan fee is. In this situation, your Medicare is "assigned" to the Advantage plan so you can use only those providers, be it an HMO or PPO or other. You dont have to buy a Part D plan.

You must continue to pay your Part B premium and your Part A premium (if applicable) to Medicare. You will also pay the Medicare Advantage premium (if it has one) to the insurance company.

Your agent will explain all of this.