Desigual Sandton City unprofessional and bad experience

I purchased an expensive bag from desigual in Sandton City last week. I discovered 2 days later that there was no stopper on the zip which meant the zip was not working. I immediately went in to the store to ask for a refund. The manager and staff were extremely unhelpful and said they only refund for damaged or broken goods and claimed that my bag was not broken and they could give me a credit note. I did not want a credit note, the bag was and is faulty and it was only 2 days since I bought the bag yet they refused to assist.I subsequently tried to call and WhatsApp Marian ***rlad who was apparently the manager to speak to but she kept avoiding my messages and calls. This is totally unacceptable to me and unless I get my refund in the next 2 days I will go to every public forum to warn the public how this business operates and i will proceed legally to obtain my refund which is due to me together with all legal costs incurred