Double Changed - No Refund

I went to BP Thorntree - Soshanguve on the 25/09/2015 and filled a tank with Diesel for R300 and later on the 02/10/2015 went there and put in Petrol for R435.61 hence I was using a different car but both transaction were paid on the same card. On Sunday 04/10/2015 at 03:37am I received an SMS showing R300 have been paid to BP Thorntree. I went to same BP and asked for Petrol Manager who told me to bring Bank Statement (Stamped) as proof. On Monday 05/10/2015 I handed him Stamped Statement in front of another Customer who had the same problem and he promised to resolve the issue same day. I got a call from him (manager) later on Monday acknowledging that they are wrong and I will get my money back as soon as he sort this with the Bank by no later than Tuesday 06/10/2015. I went there today 08/10/2015 and was told that he will come at 12H00 . I called him (manager) around 13:58PM and he told me there's nothing he can do as he is waiting for a third party yet I need my money urgently as it now affects my whole budget and worse I did not authorise them to take it. Why cant he take petty cash and pay me and sort the rest with his third-party? No money to buy food at wrk bcos of BP F***