Dear Customer,

We apologize for the inconvenience caused by the missing part of your purchase. We understand there is a major impact when missing parts are shipped, and strive to ensure all parts are always present. We are now processing a replacement part to you free of charge with our sincerest apologies. 

Again, we apologize for the trouble this caused, and hope to see you as a satisfied customer in the future.

Sincerely, 
[company name]
Il cliente afferma che al suo acquisto mancava una parte cruciale.
Genera una lettera di risposta al reclamo del cliente.