Triple Charge-No one comes back to me

On 28 November 2014 I purchased goods from the Supplier Edgars for a amount of R 829.80. However the person at the till managed to make the transaction go through 3 time thus over charging me with R 1659,60. This I can understand is some mistake. But after finding out of the triple charge I called Edgars Kolonnade and they said I must come to the store and they will sort this out. So on the 11 of December 2014 I went into the store and gave them all the documentation they need. However NOTHING ever happened or was done. On 19 Jan 2015 I called Edgars again and raised the issue again and the admin manager assured me that the issue will be sorted out within 48h. It has been a month and nothing have been done concerning this issue. I truly disappointed in the service from Edgars stores.