return policy

I bought clothes at jet eastrand mall then went to jet at sontonga to do an exchange but was told that I had to return them where I bought them as it is not within their system to assist me. Then they cashier told me that they are not authorized to do a refund for clothes not bought at their store but it doesn't say so on their invoice. If this is indeed true then it means that what jet is doing is false advertising and I am really ****ed at this. And to top it all the staff doesn't even know the number to their head office like seriously