I appreciate what you've done so far, and I want to ensure that your concern with linking to QuickBooks Payments is addressed promptly. Allow me to direct you to the right person to contact for the necessary help and support.
You can contact our Payments Support Team to verify the exact reasons for the issue. One of our specialists will review your account securely and provide a detailed explanation about the error.
To connect with our support, I recommend clicking the Help panel in your QuickBooks account and entering the specific concern you need assistance with.

Alternatively, you can log in to your Merchant's account and go to the Support tab.

Additionally, I've attached these articles for future reference in managing bank transactions and get answers to your QuickBooks Payments questions:
Feel free to post again in this thread if you need clarification on linking your QuickBooks Payments account or other banking concerns. The Community Team is always here to assist you.