I cannot gain access to my GSX account

The only contact info I can find for GSX (https://www.apple.com/support/programs/ssa/) is this:

For additional information, please contact your Apple Sales Representative or email ssa.program@apple.com.

As this falls loosely under Apple ID account security, try Contacting Apple for help with Apple ID account security - you want to choose "Get Support now"

1. Pick your location
2. "other topics"
3. enter " GSX login disabled "
4. Schedule a phone call

You need to talk to your GSX Admin. If you are the Admin then you need to call your contact person.