limited basic HD fee

I sent back a set-top box I was not using last fall (July or August of 22 I believe). Once the return was accepted, every bill I have gotten since then includes a "Limited Basic HD" Fee. I have chatted with agents on Xfinity assistant every month since then to 1) have the fee removed from current bill and 2) have it not repeat on upcoming bill. But, as expected, when next months bill comes, there is that fee again. When I chat with agents on assistant, they tell me I need to approve changes to my account to remove this service (limited basic hd). When I see the changes, before I approve them, my bill actually goes up and not down. I explain this to them and they adjust accordingly to correct it. I did this for the last two months, but neither time did that actually remove the fee from my next bill. The third and last time I was told I needed to agree to changes to remove the fee, they wouldn't adjust my bill to it's current price. Taking the fee off would actually increase my bill over $16. They said my contract for any discounts ended Dec 19, 22.  This was for my bill ending Jan 23, 23. That bill reflects that my price is the same as it always has been. I am at a loss as to how to get this corrected. Of course the closest Xfinity office is around 70 miles away. Any solutions would be appreciated!!