Over charged for a sale item, im not happy

Good day,on the 25th I was at jet to buy boys underwear.i found them on the sale rail and they ddnt have a price tag,it wasn't the only one that didn't have a price tag.when I get to the tills I made the lady aware that this underwear I want they are from a sale rail and they don't have a price tag.she went to the floor to look for another pack unfortunately she couldn't find them but came back with a different one that are not on sale.they changed me R100 for those underwear only to find out they R60.i have a proof of purchase and a picture of their actual price thats a sale price.i was disappointed that she ddnt even search on the system to find the correct sale price.she just over charged me for what?and it's not my fault that they have placed stock on the floor that do not have a price tags.so do we get over charged for that?I even sent an *** on Monday the 28th to jet customer service did get any help till today