Spar is a rip-off and their service is disgusting

The customer service at Parksquare Spar is atrocious.I am appalled by the way that my colleague and I have been treated. I purchased Rainbow Simply Chicken Viennas which was advertised in store at R36.99.Only to find out they charged me R48.99. The manager was so rude and said that the promotion only starts the next day. So apparently they advertise early. But he said he will give it to me at the sale price. He asked his cashier to give me a refund. This was understandable and reasonable. Until I checked that she gave me the wrong amount of change.My colleague and I was so angry as we already exceeded our lunch break and was already late to go back to work due to the company's mistake. The cashier then went to call the manager again and i explained that she didn't give me a full refund. She told her manager that she doesnt know whether my colleague and I have the money on us. I was so upset with this as she imp**** that we were lying and made us feel like rogues. That's defamation of character. She said this infront of another customer. I feel so embarrassed and upset. The manager failed to reprimand her and he sided with her. He only said we are the only Spar that advertises earlier. This is actually misleading customers as we are being overcharged. I was overcharged and then called a rogue. What a joke of a company. I will never shop at Spar again!!! Please save our South Africans from being ********** their hard earned money!!