Rude cashiers that cannot calculate.

I filled up 2x 5l waters and 2x 1.5l waters. I clearly told the lady it's 13 litres of water and she got very rude and charged me 14l. This is not the first time that this has happened. Last time they charged me 25r for 15l water. When I purchase a 1.5l I completely understand that it should be 2l. Which I do not mind paying. But if I fill up 2x 1.5 litres why am I charged 4l whereas 1.5x2 clearly equals 3l. So then 3x 1liters should be loaded right?

Branch: OK foods boulevard Rembrandt Mall in Paarl

Also the loyalty program were offline and my point were not allocated to my card.

I am really tired of your cashiers not being able to calculate litres and then have an attitude when corrected.

And when we got to the till the cashier and packer were inappropriately chatting and not even greeted nor acknowledged me as a customer