Sure, and that’s the right approach. We also issue refunds, but for that, the customer needs to write to us and ask.

I would suggest not requiring customers to write you for a refund. My company automatically refunds the most recent payment if the subscription is canceled within 7 days of renewal. The invoice email that we send when the subscription renews tells the customer how to get a refund. Chargebacks still happen (rarely), but if your company had this policy it would have prevented the first chargeback you mention.