Listening tests

http://englishaula.com/en/pet-exam-listening-cambridge-preliminary-english-test-video-lessons-practice-tests-exercises.php

Letters of complaint

http://www2.elc.polyu.edu.hk/cill/eiw/complaint_letter_constructor.htm

http://www.wikihow.com/Write-a-Complaint-Letter-to-a-Company
http://www.oxforddictionaries.com/words/letters-of-complaint
http://www.oxforddictionaries.com/media/words/assets/faulty-product.pdf
http://www.oxforddictionaries.com/media/words/assets/unsatisfactory-workmanship.pdf
http://www.oxforddictionaries.com/media/words/assets/disappointing-holiday.pdf
http://www.oxforddictionaries.com/media/words/assets/leaking-radiator.pdf