bp quick to charge me twice given run around

My husband went to bp malvern service station a few weeks ago.his purchase came to around R470.00.he paid for fuel and motor oil purchase. 2 days later we go back to bp to fill up n swiped our card n there was successful payment. 2 days later at 245am I received a notice from my bank stating there was another purchase at bp.we spoke to the manager preegan who said he was going to check cctv footage to check if our card was cloned.he called that afternoon to say it was not.I called fnb to cancel my card fearing the worst n they told me that bp service station had charged me twice for the one days transaction.we went back to preegan and advised to which he rep**** he would have to wait 7 working days for confirmation.2 weeks have passed and still no feedback.I have called bp malvern n spoke to Rebecca who said preegan would call n my husband spoke to deshnie who also promised feedback but none is received to date. Who gave bp permission to charge me twice for one transaction.why are they giving me the runaround.does this happen to other customers as well?it's unnerving to know they don't give a damn about refunding me but we're quick to take my money without my permission!