Credit cards not viewable in Keap Dashboard/UI when added via the API

I am adding credit cards via the REST API, but they aren’t showing up for the contact in the Keap Dashboard/UI. I know they’re being added because I can get a list of the credit cards for a contact with the API, but in the UI they do not appear. I was told by support that they have to be done manually, but we’ve used Clickfunnel’s Keap checkout and it works fine, and I’m pretty sure they’re using the API since it’s custom.

We use Max Classic in production. I’m testing this out using Keap Pro sandbox.

What is the Keap Pro sandbox app id you are using to test?