Dubble billing

I went to Legit on 13/6/2015 to refund a pair of shoes for the value of R214. The orginal purchase was done on my Edgars card. The reversal was not processed. The same day I purchased goods to the value of R364, which was charged dubble on my account. This reflects on my statement and I went back to the same branch on different occasions for them to rectify my account. The reply was that they are still busy with the quiry and requested me to call the Edgars contact centre myself in order to rectify this. I phoned 7 times already with no resolution. Ref number: ***/GO. 2 months have passed and my account is still not fixed. This reflects poorly on my credit record. HOW LONG DOES IT TAKE TO RESOLVE????!!! My patience is running low and I am beyond frustrated. I am considering to close my account.