Ted here from Shopify, thanks for posting your query!
I can see that your store is active, however, since you've mentioned that you can not sign into the account without seeing a "locked out" message - have you received an email from Shopify? Could you please check your spam, junk, social and promotional folders as well?
If you have received an email, I'd recommend replying back to them directly as soon as you have a moment.
Please let me know how this goes!