Complain

I went to clicks Mams mall on the 27th of November to buy the 50% promotion for Safeway and kambrook to my surprise after paying I was overcharged and ask the cashier if they took off the 50%discount and she said yes then I went outside to check my receipt only to find out they didn't took off the 50% I went back to her expecting her to check and refund me but she only gave me attitude, and they called the manager whe he come he explained to me that they are aware about this problem they will log a call and refund me and they promised to call the next day which is Saturday he called with his bad line and never bothered to call again. And I decided to call myself 20 times without getting any help then I called again on Sunday he told me he is still waiting for feedback he will call on Monday he didn't even call or send an sms bad service ever and attitude from their staff I want my refund asap in future they must learn to communicate with the customers and let them know about their promotions that are not valid.