Discount system is disgusting to say the least!

I was trying to send @Home a direct message so I didnt have to put them on Hello Peter but I cant seem to find an address to send my complaint. I bought a fitted sheet from Midlands Mall Pietermaritzburg and the lady who helped me said if I bought two I would get 40% off which made the price more reasonable. I then went to the till to be told that it's 20% off each which adds up to 40%. I think this is the worst type of discount system I have ever seen and is so misleading!!! I am horrified that this is starting to happen and especially for a big company such as @Home.