Refund and handling fee of 20% of goods returned the following day

Message: On the 04/07/2024 which was was Thursday afternoon, I purchased timing chain set from Boss Auto Spares Maraisburg *** branch and l bought it accordingly to what the mechanic told me was the issue with the car. Friday morning went to a different mechanic cause it did not make sense what I was told having learned from the past experiences that some car companies just over charging for something which is not a problem. Anyway the mechanic told the problem with car could be water pump or drive belt of the car which we checked and we find out indeed the problem was water pump meaning the timing chain was not needed in this regard. The problem was fixed of which I bought a new water pump at a different spares cause the one I bought the timing chain set did have Boss Auto Spares.

I took the timing chain set back to Boss Auto Spares in Maraisburg and I told I'm going to be charged 20% handling fee for a product which was available in stock and did not have to be ordered for me. And I returned the timing chain set was on Friday afternoon and on top of the 20% they did not have money to refund me. I gave them my banking details of they said that money will be transferred to my account and what was sad is that the owner of that branch was available and did not want to do the transfer saying that the wife will do it. Today is the 09/07/2024 the transfer is not done and I called regarding the transfer being done but I'm given the ran around including the owner himself. How do I get recourse regarding the 20% handling fee and my refund. What's funny is that when money was coming in service was good but when you return the goods then you are given the ran and treated like you are not an important customer, service changes from good to bad it's like you are not allowed to return goods or for them money must always go in without going out