Bad service

Last year i bought a laptop at Cash converters Midrand halfway house for R5400.Few months later the device had issues, I took it back and they booked it for repairs. They extended my warranty and the manager promised to send me the email of which he did not. I took it back twice.

When i took it back for the third time, Some buttons are not working. I told them i need a refund because he is a problem with this laptop. The manager told the staff that the buttons are working. There is nothing wrong. He was not willing to help solve the problem. What i asking for is my refund. This laptop is frustrating me.