candy ovens and samsung door interlocks

First lets start with candy built under single oven that I fitted.When it gets up to temperature it cuts off the heat and the fan.When it cools down they come back on .customer wasn`t happy so rang hoover candy and arranged a call she was told this is now how it should be for economy. my argument to the engineer was that there was too much of a temperature drop and I dint think her chocolate sponge would like it.He said they should not have booked a call as they have been told about it in the call centre temperature drop was nearly 30 degrees. Next how many of you engineers have changed samsung door interlocks that have burnt out like hotpoint I have done 2 this week and 2 last week I haven`t seen a recall on these or have I missed it.