yes cost me 48k baht for the flight back to London either that or you wait in the detention centre for another flight and I didn’t fancy doing that! But no denied entry stamp on my passport.
Happened to me at bkk they sent me back to china then from china to London had an escort all the way with me felt like a criminal then I flew from London to Vietnam and applied for a visa there got accepted and flew to dmk they keep you detained at the airport until you book a flight with the same airline and the same route you come from