not willing to assist

I found a awesome boot @the store it was marked R 79.00 when I went to the till she said it was R799.99 and they made a mistake... so I said it is fine as I really wanted it ... but just to be fair if they could @least give me a discount as I was under the impression of it been R79.00 ... when the manager was called she said she can't help me as that's the price ... I just think as a Super store as Zara they could at least be more professional and have some sort of customer service as it was there fault ... compensate for there error at least ... really disappointing !!!