Bad Customer Service

by lack of professionalism portrayed by the so called controller, when I was returning my faulty kettle I bought at Cresta mall. She made me return with this faulty product citing that I return it back where I bought it. I now with my faulty item which is about to be out of warranty next month. Since when do we have to return items bought within the same group be returned in the places we bought them? This has caused a huge inconvenience because I made means to visit South Gate branch only to be told to go to Cresta mall.