Checkers eastgate they ****** customers

Last month I bought 2 pkt of macaroni at east gate, when I check the till slip at home they charged me 3pkt,my husband called them and they asked him a till number unfortunately he didn't have a till slip with him, yesterday I went to east gate again to do my shopping, after paying my grocery I stand next to the till to check the slip, they over charged me again, I bought 2 beans they charged me 3, also lays chips I bought 2pkt ,they charged me 3, is this how checkers east gate make money by over charging their customer, imagine how many people they have ****** who don't check their till slip after paying, thus this mean every time after paying I have to stand there and check my slip,i mean this has happen 2 me for 2 months, imagine the other month I didn't check my slip, people need to be aware of checkers eastgate