Write a letter complaining about a faulty product.

Dear Sir/Madam,

This is to inform you that on (date) I bought (item) from you for the price of (amount). Unfortunately, I have discovered that this (item) is faulty and not fit for its purpose. Therefore,  I am requesting you to carry out the necessary repairs needed to restore the (item) to a working condition. 

I shall look forward to hearing from you within the next 10 days. 

Yours faithfully