I had the same experience of being denied very rudely and aggressively. Unfortunately for them, I speak particularly supercilious Hebrew, so I managed to get them to actually show me their chart with which airlines have an arrangement for their status fliers to use the Fast Track. Lo and behold, A3 are not on it. I raised a complaint with A3 about it, and they replied as follows.
Dear frb98mf,
Thank you for your email, while please allow us to extend our apologies for the inconvenience caused.
Further to the latest update, we are sorry to confirm you that fast track is currenlty available at Tel Aviv Airport for Business Class passengers only, while the service shall not be available for Gold Members.
Please note that we are in contact with Tel Aviv Airport as well as with our Marketing Division, so as we can update the relevant field of our website the soonest possible.
We do apologize for the information given and the upheaval caused due to this occurrence. Should we have any further update on this matter, we shall keep you noted.
Thank you for your time and understanding.