Elba gas stove sold brand new and oven does not work

I have used Hirshs Somerset for a few years, and the last set of purchases and post sales service has been shockingly poor. We bought an Elba gas stove, which was eventually delivered and eventually installed, only to find that the oven does not work. I reported to the salesman at Hirshs and he promised to get Elba technician to come and check, sadly nothing has happened, so now I paid R17000 and I have a broken oven with no one calls , nothing..