Can't return unsatisfactory items between different Midas stores.

I purchased a rear view mirror from Midas in Tokai, Cape Town. It states "Universal Fit" on the package. I was returning from Cape Town to East London towing a caravan and required the mirror because of a blind spot. The mirror could not be fitted to the vehicle (Land Rover Discovery) despite my best efforts. It was too late to return the item to Tokai Midas but i wasn't worried because I though I could return the item when I arrived back in East London. The Midas in Vincent, East London, said the could not take back the item because they did not it in stock. The Midas in Bowls Road, East London said that although they did stock the item they could not take it back because I purchased it from a franchise (Tokai Midas) and that they were a Corporate Midas. I would expect the item I purchased would be able to be returned to any other Midas. As a customer how am I to know that what type of Midas I am purchasing from and that there is a disconnect between one type of Midas and another. There is no difference in he signage or anything to alert the customer that one Midas is different to any other Midas. So now I am stuck with a item that is not fit for purpose and for which I have no other use. The only reason I gave two stars is because the staff who tried to assist were helpful but constrained by the internal processes.