Answer:
The answer is D.
Step-by-step explanation:
The letter of complaint is usually written in order to express one`s dissatisfaction with something. It is traditionally sent to someone/something that provide us with some kind of service (hotel, a store, TV cable operator...)
In the answer A we can only see the notification of placing an order.
Answers B and C are expressing the customers` satisfaction with the service/product.
Finally the answer D expresses a complaint on the purchased products.