Misleading price at pep

I went to pep store darras centre,I bought items on sale-one the items that was on sale was displayed at R9.99,to my supplier the amount on the till slip was different.when I questioned the cashier he told me that it is was it and when i tried to cancel the transaction I was told to leave the store and that the is nothing that he can do.I was assisted by Samukelo.my rights were violated as per the CPA.