How do I keep a restricted area citation from going on my license?

I was driving my company(tractor trailer)and I was pulled over and got a citation from a local police for what they say driving in a restricted area.

I told the officer I was told by the previous driver and other drivers with our company that it was fine to go through that area because we have a terminal in that area(in the city).

Several of our company drivers as well as the city drivers go through that area and NO ONE has ever been stopped. And to this date No One has gotten a citation nothing!

I have passed state troopers,local police,DOT and have never been stopped for over a year now in that area because I was told they do not bother us. I was headed through that area to stop at one of our accounts as well as to get fuel from our terminal in the city but they still gave me a citation.

My question is what could be a way I prohibit this for going against my license.