Kicked out of McDonald's Carlton Centre

On Good Friday the 15th of April I went to McDonald's Carlton Centre. After meeting a friend we bought burgers for an amount of R185. We decided to leave as we had a business meeting somewhere. On my way back my battery was very low & I decided to pass through McDonald's Carlton Centre again so I could quickly boost my phone battery then continue with my journey. The manager on duty approached me & said im not allowed to charge my phone unless I buy something, I was even using my own charger. I told her I did buy in the morning & I just wana boost my battery, but I dont mind making another purchase. I took my time to stand up & go to the counter coz I wanted to transfer funds to my card. She then said if I dont go buy or leave she will call security to kick me out. I then told her I buy from McDonald's Alberton almost every week but have never been treated like this, I see people charging their laptops or phones in all other McDonald's and hv never seen them being kicked out like u telling me now. As I was busy still transfering funds she quickly left & came back with 2security guards. I explained to these 2 gentlemen the whole scenario, I even opened my banking app to show them that I had made a purchase earlier at this same McDonald's, but now this manager is kicking me out while im a regular customer at McDonald's. As I was still talking to the 2security guards who completely saw the purchase I had made earlier after showing them on my banking app, this lady the manager at McDonald's quickly pulled out my charger from the plug & told me she wasn't working in the morning, she doesn't have proof that I had made a purchase so I should be kicked out. Not wanting to cause I seen I obliged, I then told her is it bcoz im black im being treated this way, this was in full view of other customers who also seemed to be shocked. My rights and dignity were trampled upon. I was treated unfairly and Im considering lega action against McDonald's Carlton Centre. I told this manager on duty that I will never set food at McDonald's Carlton Centre as she embarrassed me by kicking me out yet im a customer and have proof of my purchase earlier. How can I be kicked out just for charging my phone, she had no right to even touch my charger and pull it out of the plug. I told her I was going to next door to Nandos where I will receive better service. I am very angry and upset at this kind of treatment and would like to get a response from McDonald's head office.