Defy-ing my request

I bought a fridge in 2016 with a 5 year warranty. When I bought it apparently it was a self defrost fridge however in 2017 it started freezing in the fridge as well as the freezer and the only way to defrost it was to unplug it and leave it , this however was damaging my furniture. Defy service consultant came and fixed it in 2017 but the problem has been continuing. Yesterday a consultant came to check the fridge again and confirms that the thermostat is not working. I get a call this morning saying that they are only willing to fix the fridge and not replace it as I want.