Is you refuse chargebacks and the revenue loss from doing the chargeback and / or your cut of the reversed transaction is, as a sum, lower than the chance that a user leaves your service, then it is better for the bottom line not to allow it.
That type of "churn and burn" doesn't work long-term. Acquiring new customers has a cost, and that cost will increase the more customers you've burned. The more customers you burn, the more likely it is that potential customers will have heard something negative about your service.