Let me step in and assist you in canceling your online bill payment. But first, you can perform basic troubleshooting steps that may help you find the pay bills online button. You can check if its a browser issue or not. Please open your QuickBooks Online account in incognito/private browser.
Google Chrome: Ctrl + Shift + N
Mozilla Firefox: Ctrl + Shift + P
Safari: Command + Shift + N
Microsoft Edge: Ctrl + Shift + P
Once done, you can clear the cache on your browser to delete the outdated files that might cause a small problem when you use your QuickBooks Online.
However, if you want to cancel the payment, you can follow these steps on how:
Go to the Transactions tab, then select Expenses.
Choose the Pay Bills Online button.
Click the Sent Payments tab.
Look for the payment you want to cancel.
Select the Track Status on the payment.
Click Cancel Payment.
Also, if you want to cancel the Online Bill Pay subscription, here's how:
Click the Gear icon on the Pay Bills Online page.
Select Cancel Subscription.
Choose your cancelation reason.
Hit Cancel now.
You'll receive an email once the cancelation is complete.
You may read these articles to learn more about Online Bill Pay: