Unhappy Customer...Worst Experience Ever!

On the 20th of September at 11h23 I went to the shell garage just before the offramp to pour petrol. As I was paying for my gas the petrol attendant Keneilwe gave me the POS machine to punch in my pin and she walked away...i then waited for her to come back, eventually when she did that machine declined my transaction whereas I received a notification that funds have just been debited out of my account I even went further to check on my internet banking statement only yo find that I have been debited. She called her manager and he said yo me the transaction didn't go through so I MUST swipe my card again because the 1st one world reverse back into my account. So simply because I was running late for work I didn't wanna say much I just did as I was being ordered. After 24hrs I went on to check on my statement only to find d that I was debited twice and my funds haven't returned to the acc. No one has made an effort to take my contact details just to inform me of that transaction whatsoever. Now it's as though it's my fault that Keneilwe walked away on me and their POS machine declined my transaction!!!