Traduzione - Turco-Inglese - Öncelikle sonuna yaklaştığımız 2011 yaz sezonu...

Hi rollingmaster,
Sorry, this one has been waiting a long time!

I have made some edits, let me know if you don't agree. The most important one I think is that I specified 'you owe us' - you always owe someone something (unless in very informal spoken language as when someone has done you a favour and he can say 'you owe me!)

Also, could 'institution' be 'company'? It is not wrong but somewhat less used.


before edits:
First of all, thank you for your collaboration and showing interest in our hotel as we approach the end of the 2011 summer season. Quite a while ago, I took up a position as front office manager in this institution. According to my information, I saw that your agency still owes us. By the way, there are some complaints filed by you. However, we do not know on what grounds these complaints were filed. Could you please send us the complaint letters of the guests with invoice attachment?

However you like.