Disappointed

I saw an adverti*****t of a Telkom Huawei router at Pep store with a price of R599 and i went to buy it at Pep Krugersdorp CBD on the 27 May 2020. I was so surprised about the price escalation of R699. then i asked the cashier Bonolo and she told me that she doesnt know. I am disappointed about this as i need clarity why the price differ.