Hifi taking 2 weeks to refund! Unacceptable!

I am an extremely unhappy customer! Faulty stock was delivered to me, i send it back mid August and i have still not received my refund... Hifi answer... We are waiting for the supplier to pass credit then the refund will take place! I did not buy from your supplier! I purchased from Hifi! It is the responsibility of Hifi to refund me regardless of the credit being passed by their supplier!