Pathetic Service from Sunglass Hut

I made a purchase at sunglass hut La Lucia Mall on Black Friday 2018. I repeatedly asked the staff to make sure my purchase was done over 6 months interest free. After receiving my first statement i noticed my installment fairly low and interest being charged to my account. I have sent an email to the customer care on the 17th January 2019 and i have not received a response. I have then started calling the sunglass hut call centre, on the 24th January i spoke to Angela who advised me that she has sent a request to change the plan on my account and it would take 24 to 48 hours. This has not been done, I call back on the 30th of January and spoke to Zimkitha who said she was speaking to her supervisor to get it done immediately and she will call me back as soon as it is done. I was given a ref number ( ********** 0768) i am still waiting for a call back from Zimkitha. I called again today the 31st January 2019, 1st call i spoke to Zinni, she put me on hold for +- 20minutes and then cut the call, i then called back and spoke to Monalisha who didn't even wait to hear my whole story and she cut the call. The staff have no decency to call the client back as they have all the information and contact details so there is no excuse if the call gets cut to call the client back. I have had just about enough with this useless pathetic store. Biggest mistake i made was taking this account. I have to fight with the store to find out my installment so i can pay them and for them to correct my account this is just madness.