Luring customers to spend more with hope to get a imaginary discount

Take a lot sent me an email, which said if I spent R450 or more then I would qualify for a R200 voucher to be used with the next purchase provided I used a VISA card. I honored my part by spending R494 with my VISA card however Take a Lot is now failing to honor its promise of the discount voucher - was this a **** to lure customers in believing that if they spend more they would qualify for a voucher, this promotion runs between 01 Aug - 30 Sept but the call center says Take a Lot has run out of vouchers? how convenient?