You have the option to delete all your online data and start fresh, @rczaplinski. This feature is available for QuickBooks Online Plus and Essentials subscriptions. Let me guide you through the process.

1. Log into your QBO account.
2. Change the URL to include /purge company.
3. Confirm you want to delete your company data, type Yes.
4. Click OK.
5. Choose Wipe Data.

You can do this for accounts less than 60 days from the day it is created and is irreversible. However, for accounts over 60 days, you'll have to cancel your current account and start a new one. 
 
For detailed information, kindly visit: Delete your data and start over in QuickBooks Online.

If you need more comprehensive guidance on managing bank transactions in QuickBooks Online, I recommend checking out or saving these resources:

• Unmatch downloaded bank transactions or move them to another account
• Undo transactions from reconciliations in QuickBooks Online

I'm also including a link that covers everything you need to know about the reconciliation process:  Learn the reconciliation workflow in QuickBooks.
 
If you have any questions or need further assistance with managing your transactions in the future, feel free to leave a comment below. I'm here to help!