NO RETURN GRANTED AFTER BAD SERVICE IN 7DAY PERIOD

I bought a 3G mobile wifi modem cash on 14 Sept. I had to wait an hour in que to get info on the device and around the same time to buy the device! During the first week it stopped reading my SIM card, I phoned the call centre to log a return. The lady who helped me had such an accent that I could not understand what she is saying. I bought more airtime to ensure this is not the problem. Then the device stopped reading the sim again. I phoned the call centre again and the same lady with the bad accent picked up. I tried to log the return but was unsuccessful. Went into Cresta Telkom branch on day 9 after buying the device. Tried to return the faulty unit and was faced with a que with waiting period 3hours! I managed to speak to manager and tried to return the device. He refused and said they do not return mobile devices within out outside 7day period. I was furious. They have wasted so much of my time already just to get a device and service on it. I tried to log it within 7days.I need to return the device and get my money/shop credit back.The device is not reading my sim and no one checked that my telkom sim is supported in the telkom device when I bought it! I need my money back!