The frequent flyer Miles and More programme is cheating and abusing their customers. I tried to book a flight with miles accumulated three weeks in advance, there were seats available (I checked in advance) but both the programme site and the customer service refused to book the flight telling me there are no seats available, thus forcing me to buy the ticket. I guess they rely on the reputation of the airlines behind miles and more (Austrian in this case) but we shall not let them abuse their customers.