Potentially false marketing gimmick and very Bad service

On the week of February they were running a sale on designer perfumes: buy 2 and get 50% on the cheapest item and get extra 10% if you are using the app. I bought two perfumes one for R699 and one for 679, in total the saving was R477.30. Unfortunately (it now feels more like planned) the R679 perfume was found to be damaged and therefore could not be delivered to me. And therefore I had to forfeit the 50% saving discount. This is where my problem starts. Had I known that I will be forfeiting the 50% extra discount I would have never made the purchase in the first place. The purchase made sense when I was buying 2 items because of the extra 50% on the cheaper item. Therefore, I would have appreciated it if runway sale gave me a chance to opt to cancel the order instead of deciding for me that I’d want to go ahead with the one item. This is where their whole argument lies. I spoke to Kelly and she argued that they sent an email telling me that the product was damaged and therefore they will be making a refund to my account. And if I did not need the delivery of the other product I should have responded to the email – which I did respond to. My counter response is they communicated to me confusing messages. All these events happened on 27/February/2018. At 9:32 am I received a confirmation that my order was shipped – No indication that my order was incomplete. At 2:18 pm I receive a ticket note saying that the one item in my order was damaged - I new didn't open any ticket and in any case i already received confirmation of my order being delivered in full so i did not act on the ticket. At 5:08 pm I receive confirmation from courier that they have received my order - further confirmation that all was in order. Kelly’s argument was based on the fact that they sent me a ticket note on 27/February/2018 and I only responded on 2/March/2018 (2 days later) which was already too late to cancel the order. But by the looks of it the order was already shipped by the time they sent me that ticket note. In addition, why be selective about it, what about the fact that i was already sent confirmation that my order was shipped??