Hello there, @Mrjan.
Thanks for taking the time to reach out to us. Allow me to address your concern, so let me get this straightened out.
As of now, QuickBooks Online doesn't have an option to send statements with a balance due automatically to your customer. I can see how this feature would be helpful for you, I'd recommend sending feedback directly to our product developers for future updates.
Here's how you can send feedback:
- Click the Gear Icon.
- Select Feedback.
- Click Next and choose Feedback under Category option.
- Select Save.
For future reference, you can check this article: How to create memorized A/R reports with email reminders.
Please know that you're always welcome to post if you have any other concerns. We're always here to help.