You cannot use ShapeShift to off-board to USD or any other fiat.
However, you can buy crypto using our integrated version of Banxa. If you are on ShapeShift.com and click "Buy Crypto", a new tab will open and you will be directly transacting through Banxa. Every crypto purchase with fiat is made via Banxa at this time.
If you have issue with your Banxa purchase, please reach out to the Banxa customer support: firstname.lastname@example.org