The BA record needs to show your correct AAdvantage status. If you booked the trip prior to becoming Gold then there is a good chance BA shows you as no-status, with all the rights and privileges thereto. You need to ask BA to refresh the status on your reservation, perhaps by deleting your FF # and re-entering it. You may be able to do this yourself on ba.com.

Obviously BA Executive Club did not understand your emailed request. They thought you were asking for a status match into their program, which they evidently do not grant.