I have ways on how to delete all your data in QuickBooks Online and start a new one.
If the data is less than 60 days, you have the option to purge your account if you're using QuickBooks Online Plus and Essentials. The system deletes all data entered, and you're unable to restore or reverse them.
You can use the same user ID and a password you previously had. If you activated payroll in the account, this is the best option for you.
Additionally, you can export some of your lists to Excel so you can import them easily to the new company. Take a look at this article for more details: Move your lists to QuickBooks Online.
Let me know how everything turns out by leaving a comment below. I'm always around if you need help. Have a great weekend.