Please help!

I need some assistance please with a Samsung Galaxy S6 Edge I bought on the 10th April. The phone had a defect in the frontal glass. After having the phone for 6 days I returned it to the Vodashop in Welkom. I was promised that the phone would be replaced as it qualified as an out of the box failure. It is now the 30th April and still nothing has been done to get a reference number to replace the phone. Please help in resolving this issue as I am paying R800.00 per month for a phone I don't even have.