False advertising to make an extra buck!!!!

So I discovered Runway sale a few months ago and apart from the fact that packages take up to three weeks to be delivered I was impressed with the prices of the items and the quality.So I have spent close to R10000 already shopping away.Last week I Bought items because I received emails about the extra 10% and 15% off on the total amount purchased and of ourselves this attracted me and I started purchasing again.The coupon is loaded I see the discount,I'm happy and I pay.Then bam,shocker the amount deducted from my credit card doesn't have the discount app****.I email Runway,they way they will investigate.The next day another email comes through telling me about a special discount app**** at checkout and once again I start shopping to my despair no discount for me again as the full amount without discount is deducted again.So I send another email.Only to get this lousy reply. "As per our t's and t's.....there's nothing we can do about it basically.So I figured this coupons that you so proudly advertise is just another marketing stunt to get us to shop and once we do and we have to pay,boom no discount.Im so upset and disappointed cause now you asking for screenshots,why would I have taken a screenshot????if you say there is a coupon and I apply the coupon I expect it to work.Im so so disappointed that this is how you treat loyal customers.You might think a R200 or R300 is nothing and I should get over it,but to me that money means something especially if I was motivated to buy because of the discount coupon that you guys advertise.Im so unhappy and angry that you also just have the audacity to say no one else had this experience as if my bad experience doesn't matter.I am also a customer and I should matter!!!!!!!!!