Stripe continuing to charge member after they've cancelled

I have one member who cancelled their subscription 2 years ago on Ghost, yet has still been getting charged via Stripe. How does this happen?

When I look at the logs on Stripe, I can see that there are two customers with the same email. While one (the one with the member’s name) stopped getting charge years ago, the other one (with some auto-generated customer checkout number) continued getting charged.