I am writing this letter to draw your attention towards the poor customer service of your restaurant.
Yesterday, around 1 pm me and my friends came to your restaurant for the lunch for the birthday party of my friend and we reserved the table two days before the lunch over the phone. When we arrived at the front desk of the reception and the receptionist did not behave very well and asked us to wait for 20 minutes that was totally inconvenient / inappropriate. Afterward we got our table and we ordered food. One of my friend ordered chicken that was not properly cooked and it was cold as we asked the waitress to gave us new chicken she just reheated it. In allied to this, we ordered the white sauce pasta but they did not have the item at the time so they gave us red sauce pasta without telling or providing any satisfactory explanation. The waitress was very rude and helpless.
I expect the full refund of our terrible meal. If the refund is not possible, I expect some compensation for this. Furthermore, I would like to suggest some improvement such as provide the training to improve the customer service and quality of food.
Yours faithfully, 
I am writing this letter to draw your attention towards the poor customer service of your restaurant.
Yesterday, around 1 pm me and my friends came to your restaurant for the lunch for the birthday party of my  
friend and
 we reserved the table two days  
before
 the lunch over the phone. When we arrived at the front desk of the reception and the receptionist did not behave  
very
 well and asked us to wait for 20 minutes that was  
totally
 inconvenient / inappropriate. Afterward we  
got
 our table and we ordered food. One of my friend ordered chicken that was not  
properly
 cooked and it was  
cold
 as we asked the waitress to  
gave
 us new chicken she  
just
 reheated it. In allied to this, we ordered the white sauce pasta  
but
 they did not have the item at the time  
so
 they gave us red sauce pasta without telling or providing any satisfactory explanation. The waitress was  
very
 rude and helpless.
I  
expect
 the full refund of our terrible meal. If the refund is not possible, I  
expect
  some
 compensation for this.  
Furthermore
, I would like to suggest  
some
 improvement such as provide the training to  
improve
 the customer service and quality of food.
Yours  
faithfully
,