Unhappy Customer of Defy

I bought a Fridge from defy. Within 6 months the fridge stoped working. I called them for more for a month to give me a new fridge but they isisted in fixing it. I let them fix the fridge cause they said it did not have enough gas said the Technician from Defy. He filled the fridge with gas and checked if it leaked anywhere. And it was okay. It got cold for a month and had the same problem again. I have been calling Defy for 4 months now to come collect their friedge and give me a new fridge. And the manages say that the fridge need to be fixed 3 times befor it can be exchanged for a new fridge. I have been wanting Defy to give me a new fridge from July and now it is almost November. They keep Sending technician to come fix my fridge while they asked for proof of purchase so they can give me a new fridge. I always buy airtime to call them and they say they waiting for head office to authorise the pick up and exchange for a new fridge. Its been 4 months now. They promised me a new fridge after sending yhe proof of purchase and now they still call and want to fix my fridge. One of the managers Named Eddie when I call they answer and when they hear its Tiisetso thats talking they drop the call. I call a lot of times till my airtime is finished. I asked to speak to a different manager since eddie does not want to help. Even the other manager is not helping me with exchanging the fridge. The called in technicians again. They came and said they can not take the fridge if its not fixed. They need to fix the fridge first then they will come and take it when its ikay to give me a new fridge. I have been waiting for 4 months. And now for a new fridge and nothing yet. I need my money back now. I do not want the fridge. Please help