Ebucks is falsely advertising their discounts

I went into my ebucks profile and found that Dischem is up to 40% off and I am on the highest level, level 5, so I purchased 4 x R500 vouchers. At 40% off, I should have been charged e12000 ebucks, instead I was charged the full value of e20000, I bought this in a hurry as I am in the store. I saw 40% on my profile so I was certain that I would get the discount, clearly not, the discount doesn't exist. The vouchers are non reversible, I just lost e8000. Why are you advertising 40% on virtual vouchers if it is not an option? Once again, ebucks is luring customers with false advertising.