Unfair/ Wrongful practices

E-Mart in Pinetown, KZN is a hardware store and now also have a household/beauty section. I bought 3 sets of taps with the connectors from them. Two (2) of the taps were for the bathroom sinks which once we got home, we realised by looking at the tap size on the sink that the new ones would not fit. We did not even open the new taps out and decided to return them. The next day from purchase, in the morning I went back to E-mart to return them. The attitude was not good by first the security , then the "Manager". He scrutinised the taps and could clearly see they were still new, then asked a number of questions as to why I am returning it, then said I can go pick whatever else I need and go back to him. He kept the slip and everything else. There were a few things I decided to take and went through to pick it up. Some things I was told by their staff that they are out of stock of and new stock has not come in yet. When I got back to the "manager" he said he has to charge me a 10% charge on the refund. I asked him why as the items were bought the day before, it was untouched basically, what was the charge for. To which his response was that it is written on the slip and I should have read the slip, that is their policy/rule. He then also stated very arrogantly that I have a very bad attitude and he is just the manager , he does not make the rules. Nowhere else as far as I know do they charge you for a return, most places even give you 7 days. These people are basically *****ing. He brought a calculator and manually deducted the 10% amount from the price on the original till slip then manually overrode the till to show the price after deduction. This is how these people are. Its a lesson learned. Unless you willing to Unwilling/forcefully give E-Mart your money for nothing, do not buy from them anything you may need to return, rather buy from honest, decent places.