This looks funny but the problem actually occurred when the credit card processor tried to send a result code back to the online store's server. eyebuydirect.com's backend was bogged down at the time. So the credit card was billed but... I'll check again tomorrow to see if they finalized the order by hand.
I went to the Ramsey post office this afternoon to get stamps for the new international postcard rate. Maybe I should've given them a day or two, or even a week, after the postal rate hike because they didn't have 94-cent stamps yet. So I'll continue using 90-cent stamps and add some 2-cent stamps to make up the new rate.