They keep telling me there was no fault found

Bought a microwave from Makro last year, bought a samsung thinking it would a decent microwave. About 2 months ago the microwave stared making a zinging noise just before it switched off and continued to make this terrible noise once it was off. I took it to Makro and they sent it to samsung, i was called 2 weeks later saying that the microwave is fixed went to collect it and within a few days it was making the same noise again. I was told that the "micro switch" was replaced. Sent it back again and now they tell me that there was no fault found. how many times do i have to run up and down taking this microwave back and forth till they will replace the thing.

Absolutely pathetic, a warranty means absolutely nothing these days.

I WILL NEVER BY ANYTHING SAMSUNG AGAIN!!!!!!!!!!!!!