Overcharged

I went to Qualisave by dobsonville mall it's regarding prices when I got to the tills as I bought the C***** forest yogurt on the fridge the price says R19.95 when I got to the tills it scans R25.95 so she managed to Change it for me but since when I receive my slip via email when I got home checking my slip I can see I was overcharged by R12 regarding Rhodes Mixed Vegetables in Brine on the shelf its priced 2 for R38 but now I just realized I was charged R49.95 for 2 it's soo boring for everything not to match with shelf prices instead it's opposite instead those prices need to be checked before putting them