item purchased on sale

I purchased an item on a basis of it being on sale at R1000 when original price was R2500 on the 31-12-2015 and I then saw the same item at another outlet being sold at a normal price of R590. I then went back with the item to the original and spoke to Edgar who is the manager of the store and I explained that I have not utilised the item and I would like to get my money back as I saw it at a way cheaper price from another store. Then the manager said he cannot assist until I insisted that he take it up with the owner being AB Mohammed. I was then told I will be contacted in 40 Min's time. That time frame lapses and my wife went back to the store to find out what was the problem as we had to come back after an hour. The manager said his Boss said they cannot refund and he then told my wife that he knows the mentality we coming with. A manual credit note was given to me from a manual invoice book without any stamp or company letterhead on it which was on the 06-01-2016. I truly feel that the sale was totally wrong as it shows the shop is over pricing its items and I want my refund. Otherwise I will be forced to take the legal route the brand and store will be affected negatively.