Your credit card company is not an arbiter of contracts. They are nothing more than a payment method, and the only reason they have any process whatsoever is to try to maintain relations with the vendors who they also deal with.
If you have a contract with a vendor, decide that you don't like the product any more and decide to cancel through a chargeback, that has literally zero influence on the status of the contract with the vendor. You've simply failed to make a payment. Whether the credit card company likes your recording or not is irrelevant.
So those vendors, which in this case is Comcast, can absolutely destroy your credit rating in such a case. I mention this because invariably when payment disputes come up, someone says to just do a chargeback, yet this is no different than simply deciding to stop paying for something.
I'd always figured that one of the conditions of being able to accept a particular type of card was accepting their judgement in chargeback situations. Huh.
This recording would make a pretty effective "I dispute the debt" piece of evidence, regardless.
If Comcast sues you for payment then you go to court (or more likely to an arbiter chosen by Comcast since that's what you agreed to in your contract) where evidence matters.
But instead of that, Comcast simply reports you to the credit bureaus for non-payment. The law gives them immunity for doing so -- even if they submitted intentionally false information for malicious reasons, you can't sue them for libel. And you credit score affects your ability to function in US society: it is used for all granting of credit, for deciding whether to allow you to open a checking account, for deciding whether to hire you at a job -- it is so significant that you are forced to care. You can open a dispute of facts with the credit reporting agencies, but be prepared to spend large amounts of time doing so.
If you have a contract with a vendor, decide that you don't like the product any more and decide to cancel through a chargeback, that has literally zero influence on the status of the contract with the vendor. You've simply failed to make a payment. Whether the credit card company likes your recording or not is irrelevant.
So those vendors, which in this case is Comcast, can absolutely destroy your credit rating in such a case. I mention this because invariably when payment disputes come up, someone says to just do a chargeback, yet this is no different than simply deciding to stop paying for something.