Daylight robbery in the name of "VAT" at NTK

I'm lufuno.i went to NTK store in thohoyandou to purchase a chemical that burns grass in the yard.so I get to till the lady scans and it scans 217.80×2 which adds to 436.60 and I'm told by the cashier 501 then I paid so when I check the slip I see subtotal is 436.60 but i paid 501 so when i went bck to the store I'm told i need to pay vat in that store hence i paid 501.90 so i asked this lady who blantly told me( WITH SMIRK ATTITUDE )they have never received complaints about this thing of VAT in their store because every one that comes in their store are charged that vat ,so I asked if its 250 in the shelf y is it not showing 250 on the slip but instead it shows 217.80 she couldn't answer she just kept saying it's vat

If I were to go to any retail store they dont charge any less or more from what's on the shelf And if I see 20.00 on the SHELF and i get to the till it scans less 20.00 i pay what it scans because it might be in promo I dnt know if I'm making sense So the way NTK does its payment its misleading Subtotal:436.47 Btw:65,47 Total:501.90 That's how their slip looks So its misleading to customers because in other big retailers we are not charged in a misleading way SO WHY IS NTK PRICES WHEN GETTING TO THE TILLS ITS NOT TRANSPARENT TO THE CUSTOMERS. WHAT IS THIS BTW CHARGE THEY HAVE IN THEIR STORE THAT THEY CHARGE IN THE NAME OF VAT THIS IS TOTALLY ABSURD