Winning a chargeback isn't just refusing to pay a bill. A neutral third party confirmed you were in the right and the merchant was in the wrong, so it's unfair for the merchant to punish you for them.

Well the whole premise here is that the bill was incorrect, so why would I pay it as-is? And the billing party refused to adjust it, this is why I had to resort to a chargeback.

Partial chargebacks would be an interesting concept in this case.