That CSR doesn't seem to be correct.
When I got my Gold in May 2008, I went through the regular Amex site. I think it was July when the $125 fee showed up, and I PIF'ed it immediately. I then called Amex and told them that it was my very first call to CS and I had a problem. I said I thought the fee was waived the first year. He asked me what website I had gone through, and I told him that I had looked at several but I had applied through the regular Amex site.
I told him I had already paid the fee, but I really thought it was waived the first year. He put me on hold, and came back and said, "We want you to have an excellent experience with AMEX, so we are crediting back the fee." Within a day it was credited.
It may be worth a shot to wait until Monday when the regulars are at work and try this approach.
I received my Gold card in January 09. In the T&C it said the first YEAR's fee would be waived. It's now December. I just called to verify and was assured that the annual fee will be added in January. It shouldn't matter what month you received your card. A year is a year, not a prorated part of the year.
While it's true that the annual fee is paid in advance, the first year is waived so the OP's situation makes no sense at all.
Call back Monday, as suggested.