Bad customer service

I went to Ackerman's store the one in Atteridgeville Attlyn mall...so I had the kids T shirt that I bought in Sammy Marks Ackerman's store..it was R24.95,so I got in the store with my sister ,I only took three to four steps when I realised that I had the t shirt with me.so I went back to explain to the security that I made mistake..the security was so loud at the door saying i took the t shirt in the store.He called the manager and the manager Sibusiso did not even wanted to hear my side of the story he told the security that I have to pay for it and he was loud as if I stole the shirt..so i went home to get the receipt,,,so what angers me was that they treated me as if I am a ***** and everyone in the store was looking at me as if i stole it..so I wanted to speak to the manager again for him to explain to me as I didn't know or understand their procedures.. He basically told me that I am not the only customer there are so many people..he even went at the back for few minutes and never attended until i decided to leave the store. I called the head office ***,, ********** and they said they came back to me within 7 days.