Why you should know: the price hike of Xbox GamePass caused their unsubscribe page to crash. This could lead to someone putting it off and immediately forgetting, then getting charged for the next pass against their wishes. Cutting payment at the source will piss off Xbox and they’ll auto kick you off anyway
The only action taken against your account in case of the charge failing (so not a chargeback) is tou losing access to paid stuff, whatever it may be.
If there’s a free tier, you should be reverted to that. If there isn’t , the account obviously gets suspended entirely.
Cancelling a paid account shouldn’t result in you losing access to otherwise free-tier services.
A chargeback (taking back money after you’ve used a paid service) is a whole different can of wirms, though. Which doesn’t mean you should lose free-tier access in all situations, mind you.