Extra 5c or 10c Charge @ Shell Garage Protea Gardens Mall

Good Evening CEO or management,i am complaining regards one of your garages in Soweto Protea Gardens Mall that forever when you poor petrol you will be charge an extra 5c or 10c really this have been happening for a while now and management isn't working with us as patrons,so please this affecting our finances even if it's 5c more due to bank charges ,please hope this will be looked into a serious one why is there always an extra 5c charge.And I'm not the only motorist complaining,when you ask the petrol attendant why they do this there is forever no answer to tour question,count that extra 5c on 100 cars for the day.