What Is The Difference In Paying With A Debit Card If The Terminal Is Open Or No

I just joined greyhound road rewards because I travel with greyhound several times a year. So for joining, my first discount was supposed to be 10% off my first web-fare. I immediately tried to purchase a ticket online and it says no web fares are available for this trip. Web support says it's because the terminal isn't open. What does that matter if I'm paying with a debit card online? So I called the 1-800-231-2222 number, explained the problem, and all they can say is that is weird. Well yes, it is weird. Can you please explain because at this point I never want to travel greyhound again.