https://www.citizensadvice.org.uk/cymraeg/Defnyddwyr/template-letters/letters/consumer-template-letters/letter-to-complain-about-misdescribed-goods-including-cars-bought-from-a-private-seller/
Letter to complain about misdescribed goods bought from a private seller - Cyngor ar Bopeth
Use this template letter to complain about something you bought from a private seller.