I appreciate the screenshot you've provided, @pigeon.

You may have enabled your Online Bill Pay feature. You can turn this off by canceling it in your account settings.

Here's how:

1. Go to the Gear Icon.
2. Choose Account and Settings.
3. Select the Bill Pay menu.
4. Click the Cancel subscription link.
5. Follow the on-screen instruction to complete the process.

You can refer to this article for more insights about Online Bill Pay. 

On the other hand, if you don't want to cancel the online bill pay feature, here's how you can manually pay the bill:

1. Go to the Expenses menu.
2. Select the Expenses tab.
3. Locate the Bill transaction you want to pay.
4. From the Action column, click the drop-down.
5. Choose Make Payment.
6. Enter the payment details to complete the process.

Always feel free to leave your comments below if you have other questions about using credits in paying your vendor balance. I'm always here to help.