Poor customer service

I returned a device on the 19 or 20 May at South Gate Mall because it was freezing and very slow for a brand new device. I asked for a refund and no one communicates with me at all. I keep speaking to a Karabo via email who happens to be the technician who is the only one who cares to respond to my emails unfortunately he is not the relevant person I should be speaking to. The lady who should be assisting me named Manuku always promises to call me back but has never ever called me back on all instances. It’s really frustrating dealing with them as a company honestly