DEFY Oven not fixed

What a dissapointment. I had my DEFY oven fixed i paid R 1,800.00 for some things to be replaced. When i got it back i called them immediately advising that the food was burining, that the 160 DegC was not 160 but more like 200. I got total attitude. Now my oven has stopped working again. I called in AAA Applicances who i had used in the past numerous occasions. They advised me that the parts were not replaced and the oven was by-passed on the wiring and this has caused a burn out :( They advised that this was dangerous. I have to pay now again R 1800.00 to have fixed what should have originally been fixed. This is so annoying.