Eunice here from Shopify, thanks for posting!
I'm sorry to hear you're locked out of one of your stores. What we'll need to do here is re-sync your identity on our end, it's an easy fix but you will need to contact Shopify Support via chat or callback as we're not able to provide account-specific support in the Community at this time.
To contact Shopify Support please log into to Help Centre here. Once you're logged in, select Support > Contact Support:
Once your identity has been re-synced you should be able to log in to your store within just a few minutes. I recommend staying connected with the Shopify Support Advisor while you wait to ensure you can get back in.
Hope this helps!
Oh no! I am so sorry, I'm not sure what happened there. The website you need is help.shopify.com. Paste that into your URL bar and you should be good to go!
Let me know here if you run into any further issues.