Very Poor Customer Service From Bosch Appliances

We purchased a Bosch 600mm Gas Stove 4 plate end December. In March 3 months later the oven had a problem igniting. I took it back to Builders Zambezi where I had purchased it. After a lot of arguing and threatening to take the issue further and trying to contact the Bosch Rep (who basically tried to tell me I don't know how to operate the oven after 3 months of using it) the stove was replaced with a demo model from the floor. A month later I am having the same issue. Builders was contacted again and I requested a new stove or my money back. The service from Builders Zambezi was shocking. Bosch eventually came out to our home and claimed that the problem was fixed. After he left it still did not work. We contacted them and they asked if we wanted our money back and we said yes. Only to receive a phone call requesting an installation certificate all of a sudden. Yet when we took the stove back the first time this was not requested and the stove was fixed at Builders. Neither Builders Zambezi or Bosch are willing to help.