Just so everyone else can be made aware:

The issue here was with a non-US credit card. I have confirmed that most non-US issued credit cards DO work with my payment processor if they have a Visa, MasterCard, Discover, American-Express or JCB logo. If the credit card is issued in a country other than the US, be sure to put "00000" as your billing zip code to ensure the order processes. Additionally, if an order fails to process it could be due to a currency conversion issue with your credit card issuer (my payment processor only accepts funds in USD) so be sure to contact your issuer if there are failed attempts and 00000 was used as a billing zip code.