Can I erase everything on my account and start again?

Thank you for posting here in the Community, @grapeandbeantruc.

Erasing QuickBooks Online (QBO) data is possible. However, certain criteria should be reviewed before you can perform this. Let me provide the full details below.

If the account you're taking over is a QBO Advanced, Plus, or Essential subscription and within the 90-day signup policy, it's possible to erase all the data by purging the account. 

Here's how:

1. Sign in to your QuickBooks Online Company.

2. Once you're signed in, open this link. Alternatively, you can change the URL to include /purgecompany.

3. Example: Change https://app.qbo.intuit.com/app/homepage to https://app.qbo.intuit.com/app/purgecompany.

4. The next screen will provide a summary of the items to delete. Type YES to delete the data, then select OK.

On the other hand, if it's a QBO Simple Start subscription and/or the account has been active for more than 90 days, the only option is to cancel the subscription and start a new one.

Also, you can read this article to learn the complete process of having a fresh start with your company: Delete your data and start over in QuickBooks Online.

If you want to learn how to import your data to your new company, check out this article: Move your lists to QuickBooks Online.

Never hesitate to return to this thread if you have additional questions about managing your QBO subscription. We'll be willing to lend a hand. Keep safe, and have a good one.