Hi, it`s been a long time since I was here for the last time. I need your help with a piece of translation. As you see I havent been dealing with Turkish for a long time so now I need your help. Hope that it makes sense so far:
This is the English part:

*Imagine the following situation:
A client of yours calls you. He is obviously furious, because he has some problem with your product. After hearing his complaints, you realize that actually he had made a mistake. You try to explain that to him, but he is strongly convinced that he is right, and the more you try to make him see the truth, the more angrier he becomes with you and your company. So, you have to cope with this complicatefd issue - to make him understand what he had done (and, of course, that he should NOT do it again) and at the same time, not to offend him - i.e. to make him think that you put the blame on yourself. How would you react and what would you say to him? (take into account the fact that if he doesn't stay satisfied, he can easily stop being a client of yours!).
Please, provide your answer in 10 to 20 sentences.

And here is my translation in Turkish:
Asagidaki durum hayal edin:

Musteriniz telefon ediyor. Calistiginiz sirketin sundugu urunle ilgili sorunu oldugu icin cok kizgin gorunuyor. Sikayetlerini dinledikten sonra hata onda oldugunu anliyorsunuz. Durumu aciklamaya calisiyorsunuz fakat aciklayinca daha da kizginlasiyor. Neticede/sonuc olarak bu karisik durumdan cikmak zorundasiniz- ayni hata yeniden yapmamasi icin kalibini kirmadan nerede yanlis yaptigini gostermelisiniz. Nasil hareket ederdiniz? Ne soylerdiniz? (tatmin kalmadigi taktirde musteri olarak onu kaybetme riskini goz onunde bulundurun)

Lutfen cevabinizi 10-20 cumlede verin.

I will appreciate all your comments.
I would appreciate if the text sounds more kibar too

Anybody?

I know i ve made most of it but need some perfection in the expressions.Anybody?

Cok teshekkurler! Takdir ederim, gercekten. Insallah artik turkceyle aram artik bozulmaz. Teshekkur ederim, arkadasim