I filed an amendment for my 2023 taxes, but didn't realize I was going to be charged so much to do so. Is there a way to cancel this action?

For billing issues you can contact the TurboTax Support Phone Number

There should not be any charge to amend your return unless the change you made required you to upgrade to a higher version of the software than the version you used for the original return.  And then the charge should only be the difference between the two fees.   What did you change when you amended?