A friend was being spoken to by police and I approached him to see if he was all good but one of the police officers told me to go away and pushed me away twice (instead of just letting me walk off). I then asked him for his badge number and he did not give it to me. Then he asked me for my ID, I supplied the information and then I again asked him for his badge number and he did not give it to me instead saying I must leave the area immediately. I started to walk off and while walking I asked him again for his badge number (as I walked backwards) he did not give it to me. He then followed me (10metres) and kept saying I must leave the area but the thing is from when he told me to leave I was constantly walking away at a normal walking rate but asking him for his badge ID as he was following me then he said I am under arrest and threw me to the floor (quite forcefully, cuts etc.) even though I was leaving the scene. Back at the station they got my fingerprints, photo, DNA and charged me for failing to cease loitering, but how can they charge me for this when I was walking away and just asking for his badge number after being pushed. Can I do anything about this arrest? I have a clean criminal record and have never run into trouble with them before. Also, when in the police station they said I could have a phone call but when I asked to call someone they said after we are done in here not yet (when they were asking me questions).