The reason I am writing to you is the poor quality of a food processor which I bought in your store two weeks ago.
#The reason I am writing to you is that the quality of a food processor, which I bought in your store two weeks ago, is poor.
The reason I am writing to you is the poor quality of a food processor, which I bought in your store two weeks ago.
# The reason I am writing to you is that the quality of a food processor, which I bought in your store two weeks ago, is poor.