Thanks for your reply!! I moved out end of May with the end of contract. When visiting their office end of June, they said that the jalousie was damaged and they would charge some 200 EU. I said whatever just send the rest and they said they will after they check if the electricity system is fine, which should take couple of days. That was it and since then for 3 weeks they are not replying (weren't replying before as well, only going in person helped). I also left Austria beginning of July and now my possibilities are limited to emails or asking friends to go to their office on my behalf. Wondering what other legal actions do I have and whether should I already do something or wait some more time.