if you are within the first 60 days (90 for non-US accounts) of starting your subscription Log into your QBO account, then look at your home page URL, it ends with /homepage, replace the homepage with purgecompany and hit enter (this deletes everything in the accounting)
other wise you either delete everything one transaction at a time
or cancel this subscription and start a new one
Note: Purge does not work at all for simple start, cancel and start a new subscription
