Faults marketing from edgars

Good Morning,

So edgars runs a promotion where club members gets 15% off a purchase that's overR600. My purchase was to the value of R1610, but only recieved R180 off. I'm not great at maths, but using my cellphone calculator, R1610 - 15% gives me R241,50.

When I queried at the till points, they say that the systems works it out automatically, so I didn't want to make a fuss , as the till operator, is just following instructions.

A store as big as edgars, should get their marketing done correctly, and stop cheating and robbing their customers.