Dear Sir & Madam
I am writing to you because sport shoes which I bought last week in your shop are faulty. The shop assistant told me that I must write to you.
Firstly I must say what has happened. Yesterday I was walking across the park and suddenly I felt that it something wass wrong. When I looked down on my shoes I noticed that one of them was broken. The sole of left shoe was unsticked.
This shoes are on a guarantee and you should repair it. If it is impossible I want to take my money back because I don't want to exchange shoes on new in your shop.
I hope that you consider my complaint positively.
Yours faithfully
XYZ
chyba tak to powinno być :) doradzam skonsultowanie z kimś jeszcze, ale uważam, że nie będzie zbyt wielkich błędów :)