Worst experience of sun glass hut #willnotgoback

1) I went to sunglasses hut store at Clearwater mall on 15/07/2018, I found a pair that I liked and once I saw the price. I told them I can get it cheaper at a different store in Cresta, they said they wanted an invoice or proof of this. 2) I waited 45 min from the store in Cresta to generate the invoice and I sent it directly to them, they called the manager and she said they can’t match this because at Cresta the item was on sale, secondly she gave me a discount of 10% on the pair, she also acknowledge that terms of price matches had to be in the same mall but this was not disclosed by the sales people in the store. 3) After accepting the 10% discount, I proceeded to pay with my discovery card which I asked them should I not get a different promotional discount since I’m paying with me credit card since its advertised on the website of discovery . the sales people said no, I had to get an email confirmation from discovery as they send people emails about these promotions and that up should take it up with them 4) I call discovery today and they said no they should of deducted the discount as the merchants are aware of the promotions that’s on offer, I called sun glass hut again and they said they would give me the R11 refund as this would equate to the 500 off from using the discovery card. 5) They said I can’t get 2 different promotional discounts but the first discount was not a promotional discount from the area manager. 6) Sunglass hut calls me back (16/07/2018) saying the terms of price matches is on the receipt after I payed for the goods, they rush you so for signing the back and all they tell you at the time of purchase is that you signing that they have explained the warrantee of 2 years.

I'm complaining about the ethics behind this.