Are you guilty of improper backing if the car behind you is not at a ured distance.?

i was driving a small 1 ton dump truck. it was in a residential area.I wasnt going but 15 miles an hour.i realized i wanted to turn left down a street and was just a little to far in the intersection.i slowed the truck down to a stop and checked my 3 mirrors. i did not see any car behind me. as soon as i put it in reverse my tow hitch ball slightly collides with a car. all what happened was his liscense plate got dented and he got a very minor dent in his bumper. i am not sure if i backed into him or he hit me.i should add that my truck has a very loud beeper when it is in reverse.i got the third degree from the officer for this minor fender bender and got a citation for improper backing and the man behind me got off for a obvious ured distance violation.. the man also said that he didnt see my brake lights, reverse lights or heard the beeper.this is bogous since i proved to the police officer that it all works properly. the officer was obvious biased towards me , i can only speculate that its because he lives in this upscale neighborhood and the officer patrols it.i had a witness in the truck that i had sent walking up to the job due to him being on the clock and not knowing how long it would take. the officer even went to my job site and pulled him away from work to question him which dont make much since cause the officer already told me i was getting a ticket. the officer turned a minor traffic fender bender to a very long ordeal. i feel like my rights were violated and was treated like a criminal on a minor incident. do i have any rights?