Using a different Payment Gateway than What is Offered by Freedom
We offer other payment gateways integrations at a cost. Each proposed gateway gets reviewed by the development team, so prices may vary.
Also, as of version 8.4, we added Authorize.net emulator support so that any online payment processor that has an Authorize.net emulator can be accepted. This is done by using the Alternate URL field in the Commerce configuration screen.
You may want to contact whatever Payment Gateway to see if they have an Authroize.net emulator.
More Authorize.net Emulator support information: