This is an accepted solution.
You should still be able to access your OpenSRS account (which hosts your Shopify-purchased domain name). Once logged in, you can then transfer your domain to another provider - see here.
If you need some help with this one, you can definitely reach out to Shopify's support team and they'll be able to help you out.
I Want to Remove My Domain Name From a Closed Shopify Store. How to do it Please?
When I try to connect my Domaine name to a new store it shows me an error "A store with that domain name already exists"
Heres what proves that am owning the domain:
NOTE: I have removed the part of "shops.myshopify.com" because I thought it ill fix my problem.