Bad service and assault

I went to return cake that I bought from Engen Petroleum station in Glen Marais Convenience Centre, Kempton Park. The supervisors of the store allowed the return however told the teller not to give me the money cause he want to talk to me. The supervisor calls me by the corner to show the cakes and asks me what is the difference and I said that the one cake is in the fridge and the other was not in the fridge. i explained that the cake was bought in the morning and returned that very day after a few hours due to that we had lots of cake and I didn't need the cake anymore. He therefore said to me that he is doing me a favor and it is against the policy, I asked him to show me that it is against the policy of which he refused I ask for the manager he **** and said that he doesn't report to anyone. I therefore said to him that I am not happy with the service i have received and I am going to take a picture of him and report him, he then grabbed my phone and pushed me on the ground. All the stuff member watched and did nothing about this matter. Name of Supervisor: Walter Bruce Ramodisha