Lizzy here, I’m a Shopify support Guru.
I would be happy to look into this for you. Our system won't charge a store that's closed so I'd like to dig in, to see if it's possible there are multiple accounts. There is also a chance the store wasn't closed entirely, as you need to follow the prompts and enter you password after clicking on the option to cancel your account. This page here has a video with all of the steps.
I've sent you an email so that we can take a look at you account, and work out what has happened.
I look forward to continuing our conversation there!