R800 worth of eBucks lost

I'm very unhappy about my eBucks purchase recently. I have a screenshot I took on the eVouchers page that showed Dischem giving a discount on the vouchers. I planned my expenditure very carefully to get the maximum out of my ebucks only to realise later after my purchase that I didn't get any discount at all. I'm suppose to get 40% discount on the vouchers. Dischem and hifi corp is one of the view places where it shows as a discount, but I got nothing, which ruined my whole budget. Please realise that your advertising affects choices customers make and in my view I now lost R800! I spent just over R2000 worth of eBucks, which at 40% discount I should have payed only R1200 worth of eBucks but I payed the full amount. I would not have made this purchase without the discount that was advertised so why are you advertising and not giving?