Thank you for tips! I have made it tiny bit more readable, but all your tips will definitely use the next time!
Question; when you mention a letter, would an e-mail be fine in this case? I think this is the only possibility how I can prove that they have got it, when they reply to me. And how do you ...

Hey everybody!

Hope you don't mind that I write in English, but it is much easier to express myself this way.
It is about a voucher for a service which was bought on socialdeal, but I haven't received any service neither refund.
This is my first post, so please don't hesitate to comment or say if I ...