Cal here from Shopify, thanks for reaching out to us. When your free trial period is up, the store automatically becomes frozen if you haven't opted to add your credit card details to your account in order for a paid subscription to start. You should be able to log in to the store using the MyShopify URL that you have used, and your password. It will prompt you then to choose a paid plan. I recommend starting with the basic plan, which is 29USD a month, while you get your store designed and set up correctly.
Let me know how it goes and if there's anything I can do to assist.
Once you log back in using the original credentials, you can then, once you are logged in as the account owner, change the account owner's email address to whatever you wish. You can also change the legal name of the business. The only thing that cannot be changed is the MyShopify URL, which will always be the same.
Yes, as your free trial is over you must pick a plan in order to continue the service. There is no way to delete the MySHopify URL, which is now associated with that account and will only ever be associated with that account. As I mentioned above, it cannot be altered. I suggest chatting to our live support team, and making a request for a small extension to your free trial, should you know a little more time to familiarise yourself with the Shopify platform.
I have the same issue and I need to delete my store because of some mistakes I have there but my 14 days trial has been expired and I can't login to my admin anymore. I tried to contact your live support via email and chat but I got below page with error. I tried with different devices and browser but none of them worked.
Please help me regards this urgent matter.