Getting charged for an unused Flex box

When I was upgrading my speed for internet a while ago, I was offered an option for the Flex 4k box - for free. I received the box and never hooked it up.

For several months now, I have been receiving a fee on my bill for a "Lmtd Basic Converter". I've never had TV service at my house, so I was confused at this charge. Spoke to a rep on the phone today and they said it was because of the Flex box.

So... Xfinity is charging me a fee for a free product. These charges need to be removed from my bill and I need to be refunded all prior charges for this. If I need to return the Flex box, then you all need to send me a shipping label to do so - I am not wasting my time to drive to an Xfinity store to return a "free" product.

I'm contacting my lawyer and my state's (WA) attorney general's office.