2005 GMC Envoy Remote keyless entry seat memory control

For the last 4 years I have been using my two remotes to start my engine and open the doors. My two keys are labeled "1" and "2." Memory seats as well as the side mirrors (and I believe the radio stations) are programmed into the two memory buttons on the driver door. Using my remote is exactly the same as pressing the corresponding memory button. So if I open the doors using remote "1" then the seat will adjust according to the setting by driver "1." This stopped working so even if I use remote "1" the seats do not adjust anymore. Pressing button "1" still works. When I brought it to my GMC-certified dealer they tell me my car model does not have this feature. Now I need to prove to them that I am not imagining my last 4 years! Can anybody direct me on how to prove that I have this feature? Thanks.