The service delivery manager [removed] does not respond. How can I escalate the issue to the right department?

In QuickBooks, you can request a callback for assistance with your account issues.

To reach out to them, click the Help button in the top-right corner of your QuickBooks Online screen. Then, click on the Assistant tab and type Contact Us to view your support options. You can choose how you want to get help, whether it’s through Chat or a Callback.

For their available hours, you can read this article: Get help with QuickBooks products and services. Don't forget to select QuickBooks Online as your product.

You can always comment below if you need further assistance with your QuickBooks QuickBooks Online account.