Faulty oven

I bought a Defy oven less than six months ago from Hirsch's , brand new with 2years guarantee. 2weeks ago I switched the oven on and within 10mins it overheated and we could smell burning metal and the overhead cupboards were becoming very hot and smoky. The entire kitchen smoke up. I Logged a call with Hirsch's and the Technician only arrives a week later . He identified many faults and is going to take another week to repair the oven. Multiple faults on the oven plus almost burnt down kitchen but Hirsch's refuses to replace the oven and requests I wait and see if the oven will pack up again!!!! Why would I risk burning my kitchen down Bad feedback and, in fact the Service manager hasn't even returned my call and I need to keep calling them for service!