Store manager not giving me feedback

I bought a brand new Asus laptop for R20k on the 31 Aug 2017. It had a tendency to overheat and started crashing in less than 3months. I took it back to the store and it was refreshed twice and still crashed. Then the store recommended taking it back to the supplier to either be fixed or replaced. The turn around time is supposed to be 10-15 days; it was 20th Nov. I keep on phoning the store (about 4 times already) and the manager Maynard promises to come back to me but never does. I called the head office and they also promised to come back to me today, it's 21h25 now and no one has called me back. I'm tired of being taken for granted. I want my laptop back and fully functional. It's time to resume work and I have no laptop to use. Incredible Connections The Glen takes me for granted and it's sickening. I have lost a lot of opportunities last year already (not to mention the information lost when the laptop crashed and had to be refreshed twice) due to the dysfunctional laptop and I don't want to lose more this year.