Chargebacks are no different than simply ceasing to send in payments for a service: It sounds pat, but can haunt you years later when massive penalties and interest appear on your credit report.
The chargeback is a contractual dispute resolution process. The consumer says they shouldn't have to pay for a valid reason. The merchant gets to provide evidence otherwise. A decision is made and both parties have agreed in advance (via the merchant agreement and cardholder agreements) to be bound by that decision. This is one of the consumer protections that make using plastic safer than using cash/checks.
So you can find stories by the thousands of people who won a chargeback, and then were hounded by collections and ruined credit. Because Visa and Mastercard don't overrule contract law.
Credit cards are safer/more powerful simply because money is influencing, and he who controls the money controls the relationship. They don't override contract law, however.
Are you saying that comcast will negatively affect your credit score because you submit a chargeback to them after they failed to cancel your service?
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.
This recording would make a pretty effective "I dispute the debt" piece of evidence, regardless.
Really!
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.
The other alternative is to play their game with their customer service and get them to agree to properly cancel the service.
I believe that is indeed what the parent post meant. If you do a chargeback, that just means you did not pay the Comcast (or whatever) bill. Comcast will likely not treat that any different than if you didn't pay, if they feel the bill is valid; your account will be sent to collections, and also show up negatively on your credit report.
Dealing with small contract issues like that with a large, bureaucratic company can be like cutting your nose off to spite your face; you cause yourself more long-term damage. You may be 100% in the right, just like a pedestrian in a crosswalk; it is still in your benefit to dodge the bus.
IANAL, but in a contract dispute, at least with a small-ish charge, the best course is to pay the bill (under protest/duress; you can indicate such in the comment on the check). Then file in small-claims court. I would reserve chargebacks to companies that have scammed you (not just crappy businesses, like Comcast/etc.), fraud / identify theft, etc.
Of course, ideally you would want to get the issue cleared up before going down that route, as well.