Bad service ever and ignonance of cashiers

I had a very bad experience at supa store , I regret using my bank card at that shop at Dhlamini , they cashier double charged me and now they don't wanna reverse my money they keep on telling me that theres no such .

Im really ****ed off cause I'm using my own petrol to do those up and down going to the bank and going bank to the shop to tell them what is goin on .

What kind of a shop that can tell the bank that theres no such and my bank says its been deducted by them plz help .

Im really annoyed.