Try buying something

Hi. I have downloaded the app on my smartphone and receive the daily offers. I have been trying to purchase 1 of the offers on special on group on since last nite. it allows me to chose the item, enter my banking details and then when I click on the last option to confirm purchase, I get an error message which says \Security Code Invalid"What security code. I Called the customer care line and spoke to Louw if that's the correct spelling today at 11h09"