It has been our pleasure being part of your business, @ejlas.
You can cancel the account from your Account and Settings within your QuickBooks Online (QBO) account. I can guide you on how to do it.
Here's how:
Go to the Gear icon (⚙) and click on Account and Settings.
From the left menu, select Billing & Subscription and choose Cancel subscription.
Click Continue.
Follow the on-screen instructions to finish cancelling the account.
If you don't see the Billing and Subscription tab, then you bought QuickBooks through a mobile app store. Refer to the following article on how to cancel it through the Apple App Store or Google Play Store: Cancel your QuickBooks Online subscription.
Once done, you'd received an email notification containing your cancellation details. Also, your data will be available in read-only access for one year from the date of cancellation. See this article for more information: What happens to my QuickBooks Online data after I cancel?.