petrol extra charges to card paying consumers

This review is from personal experience with multiple Engen garages. Engen Parktown, Engen Crowthorne, Engen centurion , Engen Woodmead (both sides), and other Engen garages I didn’t mention here. There’s the trend they use where a customer using card payment option seems to pay extra to what was asked by a client. I went multiple garages and I’m amazed at all Engen garages I’ve been to they always charged me what I never asked them to charge me when it comes to petrol purchases. In these garages numerous times I’ll ask for 95 petrol of R200/ R300.00 then get charged R200.10/ R300.05 other garages like today at Woodmead Midrand I asked for 95 petrol R400.00 and got charged R400.06 I told the attendant that please charge me what I asked for and to his defense returned the response with attitude and said to me it’s the machines if you have a problem raise it inside. The issue is they say it’s the machine and all these garages seem to have the same excuse. Others will give attitude saying the R00.06 is in my car why am I raising the matter. The truth is I never asked for 95 petrol of R400.06 and made that clear from the beginning. This may seem silly but the fact remains that a machine can be set, and Engen must look into this matter because that’s ***** to overcharge a client for something they never asked. what if a consumer is asking R400 because that’s what they have in the account? I tested these theory also to BP and Sasol garages too and was impressed that Sasol machine are mostly automated and gives what was asked and BP/Shell can be manual and if the amount runs over to what you asked (they charge you what you asked not the extra cents they overlapped with/ other garages may charge you). So basically this is a thing in South Africa.