Glad to have you back, @DiaA1.

Allow me to share some clarifications regarding the availability Credit radio button in QuickBooks.

As mentioned by Rustler above, the Credit radio button can be found in the Desktop version of QuickBooks (QBDT). QBO and QBDT are two different platforms. 

QuickBooks Online is the current version that you're using. Whereas, QuickBooks Desktop is a one-time purchase accounting software to be installed on your office desktop computer.

To record vendors' refund in QBO, you may follow these steps:

1. Press on the + New button at the left pane.
2. Select on Vendor credit.
3. In the Vendor drop-down, choose your vendor.
4. Depending on how you record purchases with this vendor, enter the Category details or Item details. Usually, this is the category, product, or service you’re getting a credit for.
5. Hit on Save and close.

After that, you can now deposit the amount and use the Pay Bills to connect the bank deposit to the vendor credit. Here's a link that contains all the details about this process: Learn how to record a refund from a vendor in QuickBooks Online.

For your reference, I'm also adding this article that you can visit about entering a vendor credit and applying them to your transactions: Enter vendor credits and refunds in QuickBooks Online.

I'll be right here to help you if you have any other questions or concerns. I'll make sure you're all set. Have a lovely day!