Ted here from Shopify, thanks for reaching out to us!
When did you buy your Shopify domain? To transfer a domain to or away from Shopify, you will need to have registered your domain more than 60 days ago and have access to your original domain provider account.
If the domain is less than 60 days old, then I'd recommend waiting until this period has passed and contacting our support directly here for further assistance. Our support can help you access your Shopify account so you can start the transfer process as mentioned in this guide. If you need to access the domains admin in the meantime to point the domain to another platform or website (edit your DNS information), please let me know, I'd be happy to help.