I was writing the following sentence and I’m puzzled which one would be the correct sentence. In my humble opinion, the second sentence looks wrong as a comma is not required. The second part of the sentence "I received..," is an independent sentence, and it is better to use a conjunction like which, or that, or maybe a comma is not required at all.
I am writing this letter to express my dissatisfaction on the laptop repair service I received from you service center.
I am writing this letter to express my dissatisfaction on the laptop repair service, I received from you service center.
I am writing this letter to express my dissatisfaction on the laptop repair service that I received from you service center.
Answer
There is no need for a comma in this sentence. However, the section from ‘I received…” onward is not an independent sentence; in fact, “the laptop repair service I received from your service center” is a noun phrase, so there is no benefit to putting a comma in to break it up. You could say ‘that I received’, or (better in my opinion) ‘which I received…’, but sentence 1 as it stands (with the addition of the final r on ‘your‘) is perfectly intelligible.
And I’d definitely say ‘dissatisfaction with…’
With my editor’s hat on, I might suggest recasting the sentence to make it pithier:
“I am writing this letter to express my dissatisfaction.
Recently, I took my laptop in to your service centre…”
But that’s style, not grammar.
Attribution
Source : Link , Question Author : Nitin , Answer Author : Richard Watt