Issues With The US Mint's Budget Shipping.

I received an e-mail from the U.S. Mint on Friday, June 14th stating I made three qualifying purchases and get free budget shipping until the end of the year. I still have that e-mail. Two purchases are associated with one e-mail account and one is associated with a different e-mail account. All three are attributed to me, with my same information and same credit card. I am being denied by the U.S. Mint despite making three purchases and still having a e-mail from them saying so. I went to make my fourth purchase of the year and will be holding off temporarily. The customer service does absolutely nothing to help besides tell you that you ordered improperly basically. This is absolute nonsense. I have all three e-mails in my name, with confirmation numbers, stating I purchased so-and-so on so-and-so date. I am disgusted and feel robbed by the Mint. How can I snap some sense into them?