I booked biz class return BKK-IST online & received an email confirmation & e-ticket. Upon arriving at the airport for the flight on the Saturday I was told at checkin that my booking had been cancelled by TK & I was advised to contact the TK callcentre. At no time prior to checkin had I received anything from TK other than a confirmed booking & e-ticket. I asked to buy another ticket & was advised that biz class was full. Luckily there was one no-show & I was able to purchase another ticket. Very shabby of TK.