No Discount Received

I purchased Controlice (Head Rinse) from Clicks in Silverwater on Friday 06 January 2015 the box has a sticker on it that advises me that I will receive R10.00 off on this product - I checked my slip and found that I paid the full price on this item. The Sunday prior to that (30 January 2015) I also purchased a Controlice item (Spray) from Clicks and I didn't receive that discount either that box was also marked with the exact same sticker - I don't have that slip to prove it - but felt that since this is the second time Clicks has not given me my discount I should say something about it now. I've checked the back of the sticker and it says that this discount coupon is valid until 31 December 2015 so can Clicks please advise why the pricing on their system has been marked incorrectly and whether they plan on refunding me? Thank you.