I CANNOT GET MY REWARDS AS ADVERTISED

I have been completing surveys for this company for "rewards" for about 3 years. every 6 month or so I would request my rewards in the form of a voucher for takealot, yuppie chef or whatever. But they have changed their method of requesting rewards and I keep getting an error "Exception! Please try again later" which I duly do and again and again etc. Eventually I wrote to their help desk and for a month and nearly 40 emails later I have been trying to get them to sort out their system. But to no avail. The people on their help desk are less than helpful and cannot seem to actually do anything. Please, people DO NOT DEAL WITH THEM. you will not get your rewards - ever.