Games stores microwave under warranty

I have had the worst experience trying to get a microwave checked out, mind you, this microwave is not even a year old and it is still under warranty. Initially, when I went to Game at Eastgate the ladies there plugged in the microwave and told me that because it still works(according to them) when they plug it in, they would not take it in to check it out(this microwave was still under warranty), I then contacted the support team so they could advise further. They then logged it to get checked out. The microwave was then collected and logged to be checked. Once it was apparently ready I was then told to fetch it. This microwave is still defective and I now don't know what to do. I honestly regret buying this microwave from game stores.