Extremely disappointed and frustrated client!

I purchased a laptop online from Hifi Corp. After a week of using the laptop my screen started randomly flashing. I contacted Hifi Corp. They collected the laptop sent it for repair. This process took a month and a half and was very frustrating. I received my laptop back on the 29th of January 24 and by the 6th of February 24 my screen was flashing again. My service representative Ntombizodwa is ignoring my emails. I have also sent an email to General enquiries also not to receive an answer. I am extremely frustrated with the service and product received by Hifi Corp. This situation is affecting my studies as I am not able to complete my online assessments. I want a refund for my laptop.