May I know how old your account is? If your account is less than 90 days old, you have the option to delete all your data and start from scratch. This feature is available to QuickBooks Online Plus or Essentials subscriptions. Let me guide you on how this works.
Log in to your QuickBooks Online company.
Look at the URL in your browser's address bar. Delete all the text after the last / and enter purgecompany.
To confirm you want to delete your company data, type Yes.