Misinforming and Hostile staff at MTN Southgate

Greetings

My father bought a USB cord to charge my Samsung Galaxy A5 phone because my older one was worn out and not as effective. He then bought one at the Southgate Mall. I tried it that very day, and it didn't work at all. The following day, I went back to ask for a refund or a better charger, but the staff misinformed me as to what my father said the day before, then they were completely hostile towards me. I then insisted they give me back my handset and invoice, and I then left without any assistance.