Misleading advertising and unprofessional staff

Good day. I am currently pregnant and had a bad experience yesterday- 17.10.2021 by KIT KAT in PRETORIA WEST (contact no-***) slip ***. Very poor service from the cashier by desk number 10 not sure of her name and the so called manager or team leader mentioned her name is Julia, she was unhelpful with a don’t care attitude being rude walking away while still taking. As customer I want to pay what I see. I bought Cappy still juice 1.5lt, On promotion is shows Buy 2 for R39.99 with code not mentioning the flavours on special. ok there was only orange flavour I took it when got at the till it was R22.99 each I told the cashier the juice is on special she checked all sucking not friendly at all and just said that is not the flavour I told her in the fridge there is no other flavours only orange and it show 2 for R39.99 she act like there no way to assist. Ok I Requested for manager, Julia came checked and there was no other flavours in stock only the orange unfortunately I will have to buy on a normal price. I refused and asked for a "Rain Check" she looked lost but she a manager I asked them to void the extra amount she said she can’t but she is so called a manager of the shop. I end up taking the Juice paid the normal price but I still feel Kit Kat customer service is very poor, don't value customers. It’s a very big shop and fooling customers with prices. I feel if it was so not on promotion, mention the flavours "DONT" put codes how will I as a customer identify the code difference. I`m very disturb for spending time at the shop requesting to pay what I see and deal with a unprofessional cashier and team leader/ or manager and go out of the shop unhappy.