“However that doesn’t stop them from trying to collect payment directly from consumers. A review of some merchant agreements found online were silent on the issue of whether they can subsequently try to collect from consumers. And when we asked the major card companies whether their merchant agreements restrict this practice, only American Express responded, saying in an email that, “American Express has an established charge dispute process in place that takes into account both the Card Member and the merchant perspectives. Our policies do not prohibit a merchant from seeking to collect payment from a Card Member for a transaction that is charged back to a merchant.”

http://blog.credit.com/2015/06/think-you-won-your-credit-car...

Interesting. I guess it doesn't violate the merchant agreement...

...which makes sense in that a valid debt can't be invalidated by a chargeback. But it doesn't turn an invalid debt into a valid one either.

And if you have a contract that you cancel in accordance with the contract (e.g. making the required request to the required phone number then limiting your call to a reasonable duration after doing so), charging back charges for periods after your payment obligation ends shouldn't give them a valid basis to send you to collections, contract or no contract.

They would be unable to prove a valid debt in that case, so a dispute with the debt collector and/or credit bureaus would get it off your credit.

Yes, if he merchant is not operating in good faith, it’s easy to outmaneuver their collections efforts provided you’ve kept good documentation.

If they are operating in good faith, and your chargeback is not legitimate, expect a blemish on your credit until you settle the debt (if sent to collections).

Yup. And a smaller blemish even once paid, for something like 7 to 10 years after that. (That's the retention period for collections information on credit reports.)