Just in case anyone was putting spend to stamps.com from mid august- mid december on amex gold business card, you probably did not received your 2x. Call them up and they will 'fix' this situation. I spent over 5 calls over the fact stamps.com was no longer giving 2x, and I doubt they credited people retroactively. (They took a week to investigate and now it should be at 2x).
This is in another forum, however I feel this needs to be more widely known amongst cardholders. Amex conveniently didn't know people were not getting there miles, and most people probably will never recoup these miles.
Good news for me is shipping is 3x starting next year. I don't spend much on airfare...