Worst Customer Service in Gauteng!

I purchased an inverter from the Greenstone store in the month of March this year. I have had a lot of trouble with it and was asked to bring it to store early in May. The device was sent for assessment and given back to me a few days later. To my suprise it was still not working. After numerous calls and emails sent to the store, I was asked to come back in. I was told in store by Johannes that the supplier is responsible for the warranty and would need to assist me when I had asked if I could get refund since it is under 6 months old and being repaired for the 2nd time. I left the inverter in store on Thursday and have heard nothing since then. I got an email from Khetiwe yesterday stating that the head of department Wil contact regarding my refund request. No one has called me yet. I have sent follow up emails, messages and called and no one can tell me why I cannot return a defective product that is 3 months old. (2 months old when it malfunctioned)! My patience is really running out! Please give me my money back! And do better with your customer service!