Hi there,
It's important that you're able to change the primary address and I'll be happy to assist you with that.
When was the last time you cleared cache and cookies on your browser? Doing this will help fix most issues the site may be having. I recommend giving this a try since it fixes most issues the site may be having.
Do you get an error message when you change the abbreviation? Feel free to share more info and screenshots. I'm here to help. :)