I'm sorry to hear you're having issues connecting with our support team. I know that can be a frustrating experience, so I'm hopeful the steps I provide in this post will help get that resolved! If you're caught in a loop then this typically can be resolved by clearing your browser's cache/cookies and trying again. If that doesn't work, then trying Google Chrome Incognito mode, or a different browser should do the trick. You can also reach out to our support via Twitter or Facebook if you'd prefer. I'd also be happy to help you here via the Community if you'd like to provide further insight on what led you to try to contact our support teams.
If you do not intend to use the Shopify account and wish to avoid being charged once the trial ends, then you will need to close the account by logging in and navigating to Settings/Plans and Permissions. From there, you'll need to scroll to the bottom of the page and select "Close Store" at the bottom of the page. If you follow the prompts, then you will fully close your store, and remove the account from active billing.