Sub standard customer service

They short change me with an office chair and I was promised the delivery of the chair the following day or within a week. 2 weeks have passed and no word from them. Tried to contact the sales lady, Ivy from the Menlyn store who assisted me with the purchase with a call asking for a follow up. Sent a text to her the following day as well as their H/O WhatsApp number, those were also ignored.