TM Lewin Menlyn - bad experience

On Sunday, 4 November 2018, I was offered a 20% discount on a jacket that cost R3999.99 at the T.M. Lewin store in Menlyn. Based on the discount, I purchased the jacket but once I had paid I noticed the price was R3999.99. The salesperson, Dipuo, said that she would process a return and then charge the jacket again at the new price, but when I swiped my card the return was rejected, as it was a debit cheque card. Dipuo said she would have to do a manual refund, but was unable to do so as there was no cash in the cash register. She said that I would receive my refund as soon as they had cash and took my phone number. She also wrote out a note that T.M. Lewin owes me the 20% discount. I have received no discount back and nobody has phoned me. No one answer the phone in the store!