Bad service and worst attitude from the staff

Yesterday I went to puchase cigarettes and It so happened that I took wrong brand, hardly 5min I returned to exchange it, I was rudely told that tobacco products don't get exchanged, I requested to speak to a manage Mr Makau who attanded me after 30min waiting for him, I explained to him that there is no sign nor notice that reflect the no exchange law as he told me that unfortunately its the law that binds them not to exchange tabacco products. I further told him that as a consumer I do not have an idea about their store laws unless if it visible, he said he can go to the back office and print it out for me, which is no help to me at that point,. He refused to refund nor exchange for me... I had to buy 2nd box of cigarettes. I want my money back as it's not my fault that they keep their so important information at the back office and not visible to their customers.