Welcome to the Shopify Community! Happy to hear you're looking to start your store up again, but sorry to hear you've been having troubles doing so. When you say that it says it's unavailable, what do you mean exactly? Are you able to please share a screenshot of what you are seeing?
If you know the email address and store domain you used, try to login here. If you've forgotten your password, you can follow our instructions on how to reset this here.
If you can't remember your exact store domain (URL), or think you may be entering it incorrectly, you can double check your store name and domain through our forgot store name link. Simply enter you email address, and an email will be sent listing any store names linked to that account. From there, use your email address and the listed store name to try to login.
If you think you may have forgotten the email address associated with the account, you will need to contact our Support team directly so they can assist you further. Follow our contact link, click "Continue without logging in" and follow the prompts to contact Support.
If you would prefer to just start a new store from scratch, you can easily sign up for a new store with a 14 day trial. There is no limit to the number of stores you can open!
Let me know if you have any further questions, happy to help!
Thanks for trying my suggested steps, and sorry to hear you still haven't been able to gain access. To look into this closer, the best next step is to contact our Support team directly. To do this, you can follow our contact link here, select continue without logging in and then follow the prompts to contact Support.
Let me know if you have any troubles, I'd be happy to help!