Horrible pnp at Fourways Mall. Do not shop here

I shop at pick n pay every week without fail and there are always instances that I am overcharged for items. The prices are lower on the shelf or reduced items but it scans a different price or full price. I always go back with my slip to see the manager and obv explain that I cannot bring the goods back a week later cause I have used them but it clearly shows on my slip the date and time. The manager is very rude and tries to argue with me every time and does not refund me back my money.