Experience migrating vaulted credit cards from Network for Good?

Hi everyone! Okay, this isn't Salesforce specific, but I know others have probably felt this pain.

We have an organization that is having one heck of a time trying to migrate the vaulted credit cards from Network for Good to another payment gateway. NFG is saying that it's impossible to do so, which seems odd, in 2020, with so many other payment gateways allowing for secure transfer of vaulted credit cards.

Does anyone have any experience tackling this, aside from restarting the full recurring donation process via a new payment gateway? I could have sworn that over the last decade we've seen organizations make this migration of vaulted credit cards, but now I'm questioning my memory.