Useless!!!

I experienced a horrific service today at Hi Fi corporation Centurion Mall. I bought a gas heater from them in March 2025. Today I had to return due to it turning itself off, sometimes it doesn't want to go on, after it has turned itself off, it won't come on again. I get there and they tell me, they need to book it in for repair which will take max 21 working days. For me that's a month. I have pneumonia and arthritis. I need a heater, Im not going to work or go outside because I need to be in a warm all the time. Taking it for 21 days how is it going to help me? I bought it to serve for my needs, in this period of it being repaired why am I going to do? The lady couldn't answer. It shouldn't have any technical issues, it brand new. 2 months old!!!