Rewards deduction

On the 22rd of July I went to sasol garage at Mabopane to buy petrol unleaded, then the petrol attendant made a mistake by filling more and on me I only have enough money for what I have asked, lucky enough I have more points that would assist interested of the short fall. I then I redeem some points but to my surprise they took double from my rewards. I then logged a complain/ clarity just to find out how much did they deduct, couldn't get any help whatsoever from the garage as well as the sasol rewards customer care. I just need someone to explain to me how much they have deducted instant of sending me from pillar to post. Would appreciate that.