Want to enroll in amazon global

I have been selling on Amazon.in for past 3 years. Thinking about expanding to Amazon.com

But unable to find any SPN for the onboarding process and also if anyone out there can provide me a little bit knowledge about how the credit card system work there?

If some how after 3 months I decided to give up on my global .com selling account will there a way to remove my credit card and gst from there.

Also how much helpful is global selling support?

Any idea or suggestions related to this from any fellow sellers will be highly appreciated. Thank you