Leroy Merlin cheats customers on refunds, Treating customers unfairly.

I ordered for a coffee table for R1999 via Leroy Merlin website. Leroy Merlin's supplier ran out of stock and then cancelled the order. I requestee for a refund and to my surprise this Winnie Mudau lady tells me that i can only get R1799 - and her reason is that i paid for a DISCOUNT!!!! This is pure theft, how do i fit into what she did with her supplier. Can she just give me my money back! What legal route can i take for this - imagine if a 10 000 customers are treated like this, that is R2 million gained in her pocket at the expense of those innocent customers who are punished because her suppliers don't have stock ordered! This is ********!!! THEFT!