50% discount

I recently opened an account with Edgars on the 18th July I went to the Cresta branch to collect my card for which I was told that I have to activate my account by getting an item which I did. I then went on the 21st wanting to buy using the 50% discount which is the or current promo to my surprise as I get to the counter I was told that I don't qualify for the 50% cause its my second purchase,the activation I did they say it was my first purchase apparently entry I never got the 50% off the activation fee so when will I get my 50% they called Teballo and he said he cant help me cause I have already used my 1st purchase which is an activation which I was also not told I was made a fool when I asked for my 50% since im a new customer. I need clarity on to how these promo work cause its misleading people. The way the manager handled this issue was not professional at all I even have the whole conversation on my phone