Questionable Repairs

During Sept this year, I had to return my LG Microwave to the stores where I had purchased it. It was not working (not cooking food. not even heating up food). It was sent to LG for repairs. First I was kept waiting, because they had to get "parts", then I was told I would be credited because they couldn't find parts. Then when I started querying - all of a sudden they found parts and "repaired the microwave. I got it back on Friday (13 October) and didn't use it - as we went away for the week end. When I wanted to use it on Sunday evening - it makes the most horrific noise now (which it never made before). Prior to being "repaired" it functioned very quietly. SO great - now it works but makes such a noise. Over and above all this there's the fact that LG don't have the decency (or guts) to respond to reviews - so it makes me wonder if they don't even believe their own motto and "values"