Incomplete order

I Ordered 2 Portable Hard Drives from the Silver Lakes branch during the Black Friday Sale. When the product eventually came I found that they only shipped one Hard Drive but the invoice in the box refers to 2. I lodged a complaint and was told that they would contact me. a Week later I made a follow up and again I was told that they cannot get hold of the store, but someone will call me. Last week I phoned for the 3rd time and got the same story, but this time a "supervisor" sent me a mail to inform me the matter has been escalated. Here I am again, a week later and no feedback. My emails to the supervisor goes unanswered. What must one do to get feedback from Makro?