Local US Representative's or Senator's office and get the telephone number of WHO to speak to at that SS office about this? Your situation is really why the congressmen have staffs.
The junk this 'guard' spewed to you about service dogs is well, dog poop. And not only this guard but likely the whole guard staff needs to be educated!
Federal buildings are NOT exempt from ADA compliance, far from it. The only difference is that fines aren't imposed on them for the lack of compliance. Go figger.
Do you have this 'guard's' name? Be sure to include that in any conversations you have within the SS building's exec's and with congressmen's and senator's offices. This guy is in BIG trouble for denying you access-especially more than once. Be sure to include all the 'questions' he asked you...He is in no postion to ask inappropriate questions when he doesn't even know the LAWS. Next time? Bring a friend who can witness such stupidity.
If that all doesn't work? Call the newspapers. It would be a good 'human interest' story for them and get you IN! Where you should be to begin with!
Keep us up to date on how well you succeed, please! Hugs and hope! - j s