How does this phone scam work?

The scammer claims he needs to connect to your computer so the “Amazon Refund Server” can process your refund by connecting to your bank account.
This is done by getting the victim to download/install screen sharing software, the scammer opens a command prompt and claims it’s the secure server. The victim is told to fill in the refund amount, the scammer types an extra digit to change the 1000 to 10000, alters the displayed bank balance to show the transfer and tells the victim they can only send back the extra money via gift cards.

There’s a lot more steps but that the basics. Watch Kitboga to see it in action.