Disappointed Telkom customer

Really unhappy with Telkom as I have recently upgraded my contract but I incorrectly chose a phone which has a single Sim usage, however I looked at the reviews online and the phone is supposed to have a dual Sim, in fact the slots are there on the tray but it does not work or is not accessible for dual simcards, only when we opened the phone we realized that it's a single Sim phone, I went home called the store manager and Telkom customer service and they say that I cannot return the phone as it's now 'second hand' and cannot be exchanged, I am so disappointed with Telkom Greenstone branch and Telkom customer service as I have been with them for over 6 years. Nomthandazo Lukhele, Mildred Mabuela have given me great service but Telkom is misleading the public