First of all how did you get in touch with someone at TSD? Last year, I attempted to sign up but had questions. I called every extension on their listed phone number. It was completely automated with many loop backs. So I gave up.
If they were not able to provide a genuine person to answer a question, then they don't need my business. Besides, I question this "savings". It seems to me I can simply pull up to a truck pump, go inside and tell the cashier that I'm NON-Commercial and they don't tax me the .26c/gal commercial use rate. That right there is a big chunk of savings off the posted price at the pump.